WO2018094970A1 - Linear constant current drive circuit for led and led illuminating apparatus - Google Patents

Abstract

A linear constant current drive circuit for an LED and an LED illuminating apparatus, comprising a rectifier module (1), a serial-to-parallel conversion module (2), a first constant current control module (3), a second constant current control module (4), a third constant current control module (5) and a switch module (6). If an output voltage of the rectifier module is smaller than or equal to a first pre-set voltage threshold value, a first constant current control module and a second constant current control module respectively perform constant current control over a first LED light string (10) and a second LED light string (20) connected in parallel; if the output voltage of the rectifier module rises to be greater than the first pre-set voltage threshold value and continues to rise and is smaller than a second pre-set voltage threshold value, the serial-to-parallel conversion module controls the first constant current control module to perform constant power control over an input power of a backward stage circuit; and if the output voltage of the rectifier module rises to be greater than or equal to the second pre-set voltage threshold value, a third constant current control module performs constant current control over two light strings connected in series, thereby implementing the application of a broad input voltage.

Description

 LED linear constant current driving circuit and LED lighting device

 [0001] The present invention belongs to the field of LED driving control, and in particular, to an LED linear constant current driving circuit and an LED lighting device.

 Background technique

 [0002] In recent years, LED (Light Emitting Diode) lamps have been widely used as illumination power sources instead of conventional incandescent lamps, daylight lamps, and the like. Common LED driving methods are divided into a power supply drive and a linear drive. Among them, the linear drive is widely popularized with its simple structure and low cost.

[0003] However, the existing LED linear constant current driving circuit cannot realize the application of a wide input voltage, that is, the output load.

The number of LED lamps determines that the input voltage can only be changed within a small range. If the input voltage is lower than the operating voltage, the LED lamp cannot be lit; if the input voltage is higher than the operating voltage, the driving power consumption is increased and the temperature rises. , affect the reliability of LED lights.

[0004] In summary, the input voltage of the existing LED linear constant current driving circuit can be changed in a small range, and the application of a wide input voltage cannot be realized.

 technical problem

 [0005] An object of the present invention is to provide an LED linear constant current driving circuit and an LED lighting device, which are intended to solve the problem that the input voltage of the existing LED linear constant current driving circuit has a small variable range and cannot realize a wide input voltage. Application issues.

 Problem solution

 Technical solution

 [0006] The present invention is implemented as follows, an LED linear constant current driving circuit is connected to a first LED light string and a second LE D light string, the LED linear constant current driving circuit includes a rectifying module, and the rectifying module Rectifying the alternating current, and outputting direct current to supply power to the first LED string and the second LED string, wherein the LED linear constant current driving circuit further comprises a serial-to-parallel conversion module, a first constant current driving module, a constant current driving module, a third constant current driving module and a switching module;

[0007] the first end of the serial to parallel conversion module, the input end of the third constant current control module, and the second constant current The input end of the control module is connected to the first output end of the rectifier module, and the output end of the third constant current control module is connected to the input end of the first LED string, and the serial conversion module The two ends, the output end of the first constant current driving module, the output end of the second LED string, and the second output end of the rectifier module are connected to the ground, and the input of the first constant current control module And the output end of the first LED light string is connected to the input end of the switching module, and the voltage input end and the controlled end of the first constant current driving module and the output of the serial-to-parallel conversion module respectively The terminal is connected to the control end, and the controlled end and the output end of the second constant current driving module are respectively connected to the output end of the switching module and the input end of the second LED string;

[0008] when the output voltage of the rectifier module is less than or equal to a first preset voltage threshold 吋, the switching module is turned off, the first LED light string and the second LED light string are connected in parallel, The first constant current control module and the second constant current control module respectively perform constant current control on the first LED light string and the second LED light string; when the output voltage of the rectifier module rises to be greater than the first Presetting the voltage threshold and continuing to rise and being less than the second preset voltage threshold 吋, the serial-to-parallel conversion module adjusts the output current of the first constant current control module, and then performs constant power control on the input power of the subsequent circuit When the output voltage of the rectifier module continues to rise to be greater than or equal to a second predetermined voltage threshold, the switching module is turned on, and the first constant current control mode and the second constant current control module are turned off. The first LED light string and the second LED light string are connected in series, and the third constant current control module performs constant current control on the first LED light string and the second L ED light string.

 [0009] The present invention further provides an LED linear constant current driving circuit, which is connected to a first LED light string and a second LED light string, wherein the LED linear constant current driving circuit includes a rectifying module, and the rectifying module performs an alternating current Rectifying, and outputting direct current power for the first LED light string and the second LED light string, the LED linear constant current driving circuit further comprising a serial to parallel conversion module, a first constant current driving module, and a second constant current a driving module, a third constant current driving module and a switching module;

[0010] The first end of the serial-to-parallel conversion module, the input end of the first LED light string, and the input end of the second constant current control module are connected to the first output end of the rectifier module. The second end of the serial-to-parallel conversion module, the output end of the first constant current driving module, the output end of the third constant current control module, and the second output end of the rectifier module are connected to the ground. The input end of the first constant current control module and the output end of the first LED string are connected to the input end of the switching module, and the voltage input end and the controlled end of the first constant current driving module respectively The output of the serial to parallel conversion module is connected to the control end, and the second constant current The controlled end and the output end of the driving module are respectively connected to the output end of the switching module and the input end of the second LED string, the output end of the second LED string and the third constant current control Module input connection

[0011] when the output voltage of the rectifier module is less than or equal to a first preset voltage threshold 吋, the switching module is turned off, the first LED light string and the second LED light string are connected in parallel, The first constant current control module and the second constant current control module respectively perform constant current control on the first LED light string and the second LED light string; when the output voltage of the rectifier module rises to be greater than the first Presetting the voltage threshold and continuing to rise and being less than the second preset voltage threshold 吋, the serial-to-parallel conversion module adjusts the output current of the first constant current control module, and then performs constant power control on the input power of the subsequent circuit When the output voltage of the rectifier module continues to rise to be greater than or equal to a second predetermined voltage threshold, the switching module is turned on, and the first constant current control mode and the second constant current control module are turned off. The first LED light string and the second LED light string are connected in series, and the third constant current control module performs constant current control on the first LED light string and the second L ED light string.

 The present invention also provides an LED lighting device, which is connected to an alternating current power source, and includes a first LED light string and a second LED light string. The LED lighting device further includes the LED linear constant current driving circuit described above.

 Advantageous effects of the invention

 Beneficial effect

[0013] The LED linear constant current driving circuit provided by the present invention comprises a rectifying module, a serial-to-parallel conversion module, a first constant current driving module, a second constant current driving module, a third constant current driving module and a switching module; The output voltage is less than or equal to the first preset voltage threshold 吋, the off module is turned off, the first LED string and the second LED string are connected in parallel, and the first constant current control module and the second constant current control module respectively An LED string and a second LED string are subjected to constant current control; when the output voltage of the rectifier module rises above a first preset voltage threshold and continues to rise and is less than a second preset voltage threshold, the serial-to-parallel conversion module is first The output current of the constant current control module is adjusted, and then the input power of the subsequent circuit is controlled by constant power; when the output voltage of the rectifier module continues to rise to be greater than or equal to the second preset voltage threshold, the switch module is turned on, A constant current control mode and a second constant current control module are turned off, the first LED light string and the second LED light string are connected in series, and the third constant current control module pairs the first LED light string and the second LED light string Constant current control line, so that the AC input voltage may vary over a wide range, to achieve a wide input voltage is applied. Brief description of the drawing

 DRAWINGS

 1 is a block diagram showing the structure of an LED linear constant current driving circuit according to a first embodiment of the present invention;

2 is a circuit structural diagram of an LED linear constant current driving circuit according to a first embodiment of the present invention;

3 is a block diagram showing the structure of an LED linear constant current driving circuit according to a second embodiment of the present invention;

4 is a circuit structural diagram of an LED linear constant current driving circuit according to a second embodiment of the present invention;

5 is a block diagram showing the structure of an LED linear constant current driving circuit according to a third embodiment of the present invention;

6 is a circuit structural diagram of an LED linear constant current driving circuit according to a third embodiment of the present invention;

7 is a block diagram showing the structure of an LED linear constant current driving circuit according to a fourth embodiment of the present invention;

8 is a circuit structural diagram of an LED linear constant current driving circuit according to a fourth embodiment of the present invention;

9 is a schematic diagram showing the relationship between the input power of the subsequent stage circuit and the output voltage of the rectifier module according to an embodiment of the present invention.

Embodiments of the invention

 The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

 1 shows a block structure of an LED linear constant current driving circuit according to a first embodiment of the present invention.

 As shown in FIG. 1 , the LED linear constant current driving circuit provided in this embodiment is connected to the first LED light string 10 and the second L ED light string 20 , and the LED linear constant current driving circuit includes a rectifier module 1 and a rectifier module. The input end of 1 is connected to the AC power source AC, and the rectifier module 1 rectifies the AC power output from the AC power source AC, and outputs DC power to supply power to the first LED string 10 and the second LED string 20.

[0026] The first LED light string 10 and the second LED light string 20 are each formed by a plurality of light emitting diodes connected in series according to the cathode of the previous light emitting diode connected to the anode of the next light emitting diode. The first LED light string 10 Or the anode of the first LED in the second LED string 20 is the input end of the first LED string 10 or the second LED string 20, and the last one of the first LED string 10 or the second LED string 20 The cathode of the diode is the output of the first LED string 10 or the second LED string 20. In practical applications, the number of L ED lamps in the first LED string 10 and the number of LED lamps in the second LED string 10 may be equal or unequal, ie, The forward conduction voltage of one LED string 10 and the forward conduction voltage of the second LED string 20 may or may not be equal.

 [0027] The LED linear constant current driving circuit further includes a serial to parallel conversion module 2, a first constant current driving module 3, a second constant current driving module 4, a third constant current driving module 5, and a switching module 6.

 [0028] The first end of the serial-to-parallel conversion module 2, the input end of the third constant current control module 5, and the input end of the second constant current control module 4 are connected to the first output end of the rectifying module 1, and the third constant current The output end of the control module 5 is connected to the input end of the first L ED string 10, the second end of the serial-to-parallel conversion module 2, the output end of the first constant current driving module 3, and the output end of the second LED string 20 and The second output end of the rectifier module 1 is connected to the ground. The input end of the first constant current control module 3 and the output end of the first LED light string 10 are connected to the input end of the switching module 6, and the first constant current driving module The voltage input terminal and the controlled terminal of the third constant current driving module 4 are respectively connected to the output end and the control terminal of the serial-parallel driving module 2, and the output terminal and the output terminal of the second constant current driving module 4 respectively correspond to the output terminal and the second terminal of the switching module 6. The input terminals of the LED string 20 are connected.

 [0029] When the output voltage of the rectifier module 1 reaches the forward conduction voltage 第一 of the first LED string 10 or the second LED string 20, the output voltage of the rectifier module 1 is less than or equal to the first preset voltage threshold, The first LED string 10 and the second LED string 20 are connected in parallel, and the first constant current control module 3 and the second constant current control module 4 respectively respectively pair the first LED string 10 and the second LED The light string 20 performs constant current control, and the third constant current control module 5 does not perform constant current control on the LED light string; when the output voltage of the rectifier module 1 rises to be greater than the first preset voltage threshold and continues to rise and is less than the second preset voltage Threshold 吋, the serial-to-parallel conversion module 2 adjusts the output current of the first constant current control module 3, and then performs constant power control on the input power of the subsequent stage circuit; when the output voltage of the rectifier module 1 continues to rise to be greater than or equal to the second The preset voltage threshold 吋, the switching module 6 is turned on, the first constant current control module 3 and the second constant current control module 4 are turned off, and the first LED string 10 and the second LED string 20 are connected in series, the third constant Flow Control Module 5 the first LED string 10 and the second LED string 20 constant current control.

 [0030] In the embodiment of the present invention, the latter stage circuit specifically includes a serial to parallel conversion module 2, a first constant current control module 3, a second constant current control module 4, a third constant current control module 5, and a gate module 6 The circuit portions of the first LED string 10 and the second LED string 20.

[0031] In the embodiment of the present invention, specifically, when the output voltage of the rectifier module 1 continues to rise to be greater than or equal to the second preset voltage threshold, the serial-to-parallel conversion module 2 controls the first constant current control module 3 to be turned off. Peer, by The output voltage of the second constant current control module 4 is greater than the first reference voltage, and therefore, the second constant current control module 4 is also in an off state.

 [0032] In the embodiment of the present invention, the first preset voltage threshold, the second preset voltage threshold, and the third preset voltage threshold may be set according to actual conditions, and no limitation is made herein.

 [0033] In the actual application, the rectifier module 1 may be a bridge rectifier circuit, or may be other types of rectifier circuits, and is specifically set according to actual conditions, and is not limited herein.

 [0034] In the embodiment of the present invention, the voltage value of the AC power source AC may be 110V~220V, that is, the input AC voltage may vary within 110V-220V, so that the LED linear constant current driving circuit realizes the application of the wide input voltage. In the process of input voltage change, the output current of the first constant current control module 3 is adjusted by the serial-to-parallel conversion module 2, thereby adjusting the power of the first LED string 10, so that the input power of the subsequent stage circuit The LED linear constant current driving circuit provided by the embodiment of the present invention removes the filter capacitor connected in parallel with the output end of the rectifier module 1 and improves the power factor of the circuit.

 2 shows a circuit configuration of an LED linear constant current driving circuit according to a first embodiment of the present invention.

 As shown in FIG. 2, as an embodiment of the present invention, the first constant current control module 3 includes a first operational amplifier E Al , a first bypass transistor N1 , and a first resistor R1 .

 [0037] The non-inverting input terminal of the first operational amplifier EA1 is the voltage input end of the first constant current control module 3, and the output end of the first operational amplifier EA1 is connected with the control terminal of the first switching transistor N1 as the first constant current. The controlled end of the control module 3, the high potential end of the first switch N1 is the input end of the first constant current control module 3, and the low potential end of the first switch N1 is common to the first end of the first resistor R1 Connected to the inverting input terminal of the first operational amplifier EA1, the second end of the first resistor R1 is the output end of the first constant current control module 3.

 [0038] As an embodiment of the invention, the second constant current driving module 4 includes a second operational amplifier EA2, a second switching transistor N2, and a second resistor. The non-inverting input terminal and the output terminal of the second operational amplifier EA2 are respectively connected to the control terminals of the first reference voltage source and the second switch transistor N2, and the high potential end of the second switch transistor N2 is the second constant current drive module 4 The first end of the second resistor R2 is connected to the inverting input terminal of the second operational amplifier EA2, and the first end and the second end of the second resistor R2 are respectively The second constant current drives the controlled end and the output of the module 4.

[0039] As an embodiment of the present invention, the third constant current driving module 5 includes a third operational amplifier EA3, a third The switch N2 and the third resistor R3 are closed. The non-inverting input terminal and the output terminal of the third operational amplifier EA3 are respectively connected to the control terminals of the first reference voltage source and the third switch transistor N3, and the high potential end of the third switch transistor N3 is the third constant current drive module 5 The input terminal, the low terminal of the third switch N3 and the first end of the third resistor R3 are connected to the inverting input end of the third operational amplifier EA3, and the second end of the third resistor R3 is the third constant current drive. The output of module 5.

 In the embodiment of the invention, the first reference voltage source provides a first reference voltage Vref for the second operational amplifier EA2 and the third operational amplifier EA3.

 In the embodiment of the present invention, the first bypass transistor N1, the second bypass transistor N2, and the third bypass transistor N3 may each be an NMOS transistor, and the gate, the source, and the drain of the NMOS transistor are respectively The control terminal, the low potential terminal and the high potential terminal of the N1 (or the second bypass transistor N 2 or the third bypass transistor N3). Of course, the first switch N1, the second switch N2, and the third switch N3 can also be implemented by using a triode or a field effect transistor, and there is no limitation.

 [0042] As an embodiment of the invention, the serial-to-parallel conversion module 2 includes a first filter capacitor C1, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a fourth switch N4. The switch N5, the first amplifier Ampl, the second amplifier Amp2, and the comparator Compl.

 [0043] The first end of the fourth resistor R4 and the second end of the fifth resistor R5 are respectively a first end and a second end of the serial-to-parallel conversion module 2, and a second end of the fourth resistor R4, the first filter capacitor C1 The first end of the first amplifier, the non-inverting input of the first amplifier Ampl and the non-inverting input of the comparator Comp1 are connected to the first end of the fifth resistor R5, and the second end of the first filter capacitor C1 and the second output of the rectifier module 1 The terminal connection, the control terminal and the high potential terminal of the fourth switch N4 are respectively connected to the output end of the first amplifier Ampl and the power supply, and the low potential end of the fourth switch N4 is connected with the first end of the sixth resistor R6. The second terminal of the sixth resistor R6 and the first terminal of the seventh resistor R7 are connected to the inverting input terminal of the second amplifier Amp2, and the non-inverting input terminal of the second amplifier Amp2 is connected to the inverting input terminal of the first amplifier Ampl. The first reference voltage source is connected, the output end of the second amplifier Amp2 is connected to the second end of the seventh resistor R7 as the output end of the serial-to-parallel conversion module 2, and the inverting input terminal of the comparator Comp1 is connected to the second reference voltage source. , the fifth control unit N5 control terminal and A second output terminal and the output terminal of a rectifier module potential terminal respectively connected to a comparator Comp, Jian fifth switch tube N5 is higher potential side is serial converter control terminal module 2.

[0044] In the embodiment of the present invention, the resistance of the third resistor R3 is smaller than the resistance of the second resistor R2, and the third resistor R The resistance of 3 is smaller than the resistance of the first resistor R1 to ensure that the first LED string 10 and the second LED string 20 are switched from a parallel connection to a series connection, and the second switch N2 is in an off state, ensuring The second cross flow control module 4 stops working.

 [0045] As an embodiment of the invention, the bypass module 6 is a diode D1. The anode and cathode of diode D1 are the input and output of the shut-off module 6, respectively.

[0046] Compared with the conventional LED linear constant current driving circuit, the LED linear constant current driving circuit provided by the embodiment of the present invention removes the filtering capacitor connected in parallel to the output end of the rectifying module 1, and connects the first filtering capacitor C1 to the fourth resistor R4. Between the common end of the fifth resistor R5 and the second output of the rectifier module 1, the LED linear constant current driving circuit can achieve a high power factor.

[0047] The working principle of the LED linear constant current driving circuit provided by this embodiment is as follows:

[0048] As shown in FIG. 2, when the output voltage VIN of the rectifier module 1 reaches the forward conduction voltage 第一 of the first LED string 10 or the second LED string 20, the output voltage VIN of the rectifier module 1 is less than or equal to the first a preset voltage threshold, wherein the output voltage VIN of the rectifier module 1 passes through the voltage divider VT of the fourth resistor R4 and the fifth resistor R5 is less than or equal to the first reference voltage _Vre f, and the diode D1 is turned off, the first LED string 10 and the second LED string 20 are connected in parallel, the fourth switch N4 is turned off, and the voltage of the non-inverting input of the first operational amplifier EA1 is the first reference voltage Vref. Since the resistance of the third resistor R3 is smaller than the resistance of the first resistor R1, the first constant current control module 3 performs constant current control on the first LED string 10 such that the current flowing through the first LED string 10 is 11 = Vref/Rl, the third constant current control module 5 does not perform constant current control on the first LED string 10; meanwhile, the second constant current control module 4 performs constant current control on the second LED string 20, so that the flow through The current I 2 of the two LED string 20 is Vref/R2. The current flowing through the first LED string 10 and the second LED string 20 can be adjusted by adjusting the values of the first reference voltage Vref, the first resistor R1, and the second resistor R2, respectively.

[0049] When the output voltage VIN of the rectifier module 1 rises above the first preset voltage threshold and continues to rise and is less than the second predetermined voltage threshold 吋, the output voltage VIN of the rectifier module 1 passes through the fourth resistor R4 and the fifth resistor R5. The divided voltage VT is greater than the first reference voltage Vref, and the fourth switching transistor N4 is turned on. Thereafter, the series-parallel conversion module 2 starts to adjust the input voltage of the first constant current control module 3, and then flows through the first LED. The current II of the string 10 is adjusted. Specifically, the voltage outputted by the series-parallel conversion module 2 to the non-inverting input terminal of the first operational amplifier EA1 is Vref-((VT-Vref)xR7)/R6, and the current flowing through the first LED string 10 is 11=[Vref- ((VT-Vref)xR7)/R6]/Rl = VT increases as the output voltage VIN of the rectifier module 1 increases, The output current II is reduced. Since the input power of the subsequent stage circuit is P=VIN*I1, adjusting the size of II can make the input power of the latter stage basically remain unchanged.

[0050] When the output voltage VIN of the rectifier module 1 continues to rise to be greater than or equal to the second predetermined voltage threshold 吋, the output voltage VIN of the rectifier module 1 passes through the voltage divider VT of the fourth resistor R4 and the fifth resistor R5 is greater than or equal to the first The second reference voltage VR, the comparator Compl controls the fifth switch N5 to be turned on, the first switch N1 is turned off, the first constant current drive module 3 stops working, the diode D1 is turned on, and the rectifier module 1 is adjusted. The values of the output voltage VIN, the fourth resistor R4, and the fifth resistor R5 are such that VT>VR, and the output voltage VIN of the rectifier module 1 reaches the first LED string 10 plus the turn-on voltage of the second LED string 20. Then, the first LED string 10 and the second LED string 20 are connected in series, and the third constant current control module 5 performs constant current control on the first LED string 10 and the second LE D string 20, so that the flow passes through The current I3 = V ref / R3 of the first LED string 10 and the second LED string 20. Since the resistance of the third resistor R3 is smaller than the resistance of the second resistor R2, the voltage of the low potential terminal of the second bypass transistor N2 (the non-inverting input terminal of the second operational amplifier EA2) is greater than the first reference voltage Vref, therefore, The second operational amplifier EA2 outputs a low level, the second switching transistor N2 is turned off, and the second constant current control module 4 stops operating.

 [0051] As can be seen from FIG. 9, as the output voltage VIN of the rectifier module 1 changes, the input power of the subsequent circuit remains substantially unchanged, so that the voltage of the input alternating current can be varied within a large range, and It ensures that the input power of the latter circuit is basically unchanged, and the high power factor is achieved.

 3 shows a block structure of an LED linear constant current driving circuit according to a second embodiment of the present invention. The embodiment adjusts the connection relationship of the third constant current control module 5 on the basis of the first embodiment.

[0053] As shown in FIG. 3, the LED linear constant current driving circuit provided by the embodiment of the present invention is connected to the first LED light string 10 and the second LED light string 20, and the LED linear constant current driving circuit includes a rectifier module 1 and a rectifier module. The input end of 1 is connected to the AC power source AC, and the rectifier module 1 rectifies the AC power output from the AC power source AC, and outputs DC power to supply power to the first LED string 10 and the second LED string 20.

 [0054] The LED linear constant current driving circuit further includes a serial to parallel conversion module 2, a first constant current driving module 3, a second constant current driving module 4, a third constant current driving module 5, and a switching module 6.

[0055] The first end of the serial-to-parallel conversion module 2, the input end of the first LED light string 10, and the input end of the second constant current control module 4 are connected to the first output end of the rectifier module 1, and the serial-to-parallel conversion module 2 Second end, first constant current drive The output end of the module 3, the output end of the third constant current control module 5 and the second output end of the rectifying module 1 are connected to the ground, and the input end of the first constant current control module 3 and the output end of the first LED light string 10 The voltage input terminal and the controlled terminal of the first constant current driving module 3 are respectively connected to the output end and the control end of the serial-to-parallel conversion module 2, and the second constant current driving module 4 is connected. The control terminal and the output terminal are respectively connected to the output terminal of the switching module 6 and the input terminal of the second LED lamp string 20, and the output terminal of the second LED lamp string 20 is connected to the input terminal of the third constant current control module 5.

[0056] When the output voltage of the rectifier module 1 reaches the forward conduction voltage 第一 of the first LED string 10 or the second LED string 20, the output voltage of the rectifier module 1 is less than or equal to the first preset voltage threshold, The first LED string 10 and the second LED string 20 are connected in parallel, and the first constant current control module 3 and the second constant current control module 4 respectively respectively pair the first LED string 10 and the second LED The light string 20 performs constant current control, and the third constant current control module 5 does not perform constant current control on the LED light string; when the output voltage of the rectifier module 1 rises to be greater than the first preset voltage threshold and continues to rise and is less than the second preset voltage Threshold 吋, the serial-to-parallel conversion module 2 adjusts the output current of the first constant current control module 3, and then performs constant power control on the input power of the subsequent stage circuit; when the output voltage of the rectifier module 1 continues to rise to be greater than or equal to the second The preset voltage threshold 吋, the switching module 6 is turned on, the first constant current control module 3 and the second constant current control module 4 are turned off, and the first LED string 10 and the second LED string 20 are connected in series, the third constant Flow Control Module 5 the first LED string 10 and the second LED string 20 constant current control.

 [0057] In the embodiment of the present invention, the latter stage circuit specifically includes a serial to parallel conversion module 2, a first constant current control module 3, a second constant current control module 4, a third constant current control module 5, and a bypass module 6. The circuit portions of the first LED string 10 and the second LED string 20.

 [0058] In the embodiment of the present invention, specifically, when the output voltage of the rectifier module 1 continues to rise to be greater than or equal to the second preset voltage threshold, the serial-to-parallel conversion module 2 controls the first constant current control module 3 to be turned off. Similarly, since the output voltage of the second constant current control module is greater than the first reference voltage, the second constant current control module is also in an off state.

[0059] In the embodiment of the present invention, the voltage value of the AC power source AC may be 110V~220V, that is, the input AC voltage may vary within 110V-220V, so that the LED linear constant current driving circuit realizes the application of the wide input voltage. In the process of input voltage change, the output current of the first constant current control module 3 is adjusted by the serial-to-parallel conversion module 2, thereby adjusting the power of the first LED string 10, so that the power of the first stage circuit is The input power is substantially unchanged; and compared with the conventional LED linear constant current driving circuit, the LED linear constant current driving circuit provided by the embodiment of the invention removes the filtering capacitor connected in parallel to the output end of the rectifier module 1, thereby improving the power factor of the circuit.

 4 shows a circuit configuration of an LED linear constant current driving circuit according to a second embodiment of the present invention.

[0061] As shown in FIG. 4, the circuit structure of each module in the LED linear constant current driving circuit provided by this embodiment is completely the same as the circuit structure of each module in the LED linear constant current driving circuit provided by an embodiment. For details, please refer to The related descriptions in the first embodiment corresponding to FIG. 2 and FIG. 2 are not described herein again.

[0062] The working principle of the LED linear constant current driving circuit provided by this embodiment is as follows:

[0063] As shown in FIG. 4, when the output voltage VIN of the rectifier module 1 reaches the forward conduction voltage 第一 of the first LED string 10 or the second LED string 20, the output voltage VIN of the rectifier module 1 is less than or equal to the first a preset voltage threshold, wherein the output voltage VIN of the rectifier module 1 passes through the voltage divider VT of the fourth resistor R4 and the fifth resistor R5 is less than or equal to the first reference voltage _Vre f, and the diode D1 is turned off, the first LED string 10 and the second LED string 20 are connected in parallel, the fourth switch N4 is turned off, and the voltage of the non-inverting input of the first operational amplifier EA1 is the first reference voltage Vref. The first constant current control module 3 performs constant current control on the first LED light string 10 such that the current flowing through the first LED light string 10 is I==Vref/Rl; meanwhile, since the resistance of the third resistor R3 is smaller than the first The resistance of the resistor R1, therefore, the second constant current control module 4 performs constant current control on the second LED string 20 such that the current flowing through the second LED string 20 is I2=Vref/R2, and the third constant current control module 5 The second LED string 20 is not subjected to constant current control. The current flowing through the first LED string 10 and the second LED string 20 can be adjusted by adjusting the values of the first reference voltage Vref, the first resistor R1, and the second resistor R2, respectively.

[0064] When the output voltage VIN of the rectifier module 1 rises above the first preset voltage threshold and continues to rise and is less than the second predetermined voltage threshold 吋, the output voltage VIN of the rectifier module 1 passes through the fourth resistor R4 and the fifth resistor R5. The divided voltage VT is greater than the first reference voltage Vref, and the fourth switching transistor N4 is turned on. Thereafter, the series-parallel conversion module 2 starts to adjust the input voltage of the first constant current control module 3, and then flows through the first LED. The current II of the string 10 is adjusted. Specifically, the voltage outputted by the series-parallel conversion module 2 to the non-inverting input terminal of the first operational amplifier EA1 is Vref-((VT-Vref)xR7)/R6, and the current flowing through the first LED string 10 is 11=[Vref- ((VT-Vref)xR7)/R6]/Rl = As the output voltage VIN of the rectifier module 1 increases, VT increases, and the output current II decreases, since the input power of the subsequent stage circuit is P=VIN*I1 Therefore, adjusting the size of II allows the input power of the subsequent stage circuit to remain substantially unchanged. [0065] When the output voltage VIN of the rectifier module 1 continues to rise to be greater than or equal to the second predetermined voltage threshold 吋, the output voltage VIN of the rectifier module 1 passes through the voltage divider VT of the fourth resistor R4 and the fifth resistor R5 is greater than or equal to the first The second reference voltage VR, the comparator Compl controls the fifth switch N5 to be turned on, the first switch N1 is turned off, the first constant current drive module 3 stops working, the diode D1 is turned on, and the rectifier module 1 is adjusted. The values of the output voltage VIN, the fourth resistor R4, and the fifth resistor R5 are such that VT>VR, and the output voltage VIN of the rectifier module 1 reaches the first LED string 10 plus the turn-on voltage of the second LED string 20. Then, the first LED string 10 and the second LED string 20 are connected in series, and the third constant current control module 5 performs constant current control on the first LED string 10 and the second LE D string 20, so that the flow passes through The current I3 = V ref / R3 of the first LED string 10 and the second LED string 20. Since the resistance of the third resistor R3 is smaller than the resistance of the second resistor R2, the voltage of the low potential terminal of the second bypass transistor N2 (the non-inverting input terminal of the second operational amplifier EA2) is greater than the first reference voltage Vref, therefore, The second operational amplifier EA2 outputs a low level, the second switching transistor N2 is turned off, and the second constant current control module 4 stops operating.

 [0066] As can be seen from FIG. 9, as the output voltage VIN of the rectifier module 1 changes, the input power of the subsequent stage circuit remains substantially unchanged, so that the voltage of the input alternating current can be varied within a large range, and It ensures that the input power of the latter circuit is basically unchanged, and the high power factor is achieved.

 5 shows a block structure of an LED linear constant current driving circuit according to a third embodiment of the present invention.

 [0068] As shown in FIG. 5, the LED linear constant current driving circuit provided by the embodiment of the present invention is connected to the first LED light string 10 and the second LED light string 20, and the LED linear constant current driving circuit includes the rectifier module 1 and the second The filter capacitor C2, the input end of the rectifier module 1 is connected to the AC power source AC, and the first end and the second end of the second filter capacitor C2 are respectively connected to the first output end and the second output end of the rectifier module 1, respectively, the rectifier module 1 and The second filter capacitor C 2 rectifies and filters the alternating current output from the alternating current power source AC, and outputs the direct current to supply power to the first L ED string 10 and the second LED string 20 .

[0069] wherein, the first LED light string 10 and the second LED light string 20 are sequentially connected in series by a plurality of light emitting diodes in accordance with the cathode of the previous light emitting diode connected to the anode of the next light emitting diode, and the first LED light string 10 is sequentially connected. Or the anode of the first LED in the second LED string 20 is the input end of the first LED string 10 or the second LED string 20, and the last one of the first LED string 10 or the second LED string 20 The cathode of the diode is the output of the first LED string 10 or the second LED string 20. In practical applications, the number of L ED lamps in the first LED string 10 and the number of LED lamps in the second LED string 10 may be equal or unequal, ie, The forward conduction voltage of an LED string 10 and the forward voltage of the second LED string 20 may be equal.

[0070] The LED linear constant current driving circuit further includes a serial to parallel conversion module 2, a first constant current driving module 3, a second constant current driving module 4, a third constant current driving module 5, and a switching module 6.

[0071] The first end of the serial-to-parallel conversion module 2, the input end of the third constant current control module 5, and the input end of the second constant current control module 4 are connected to the first output end of the rectifier module 1, and the third constant current The output end of the control module 5 is connected to the input end of the first L ED string 10, the second end of the serial-to-parallel conversion module 2, the output end of the first constant current driving module 3, and the output end of the second LED string 20 and The second output end of the rectifier module 1 is connected to the ground. The input end of the first constant current control module 3 and the output end of the first LED light string 10 are connected to the input end of the switching module 6, and the first constant current driving module The voltage input terminal and the controlled terminal of the third constant current driving module 4 are respectively connected to the output end and the control terminal of the serial-parallel driving module 2, and the output terminal and the output terminal of the second constant current driving module 4 respectively correspond to the output terminal and the second terminal of the switching module 6. The input terminals of the LED string 20 are connected.

 [0072] When the output voltage of the rectifier module 1 reaches the forward conduction voltage 第一 of the first LED string 10 or the second LED string 20, the output voltage of the rectifier module 1 is less than or equal to the first preset voltage threshold, The first LED string 10 and the second LED string 20 are connected in parallel, and the first constant current control module 3 and the second constant current control module 4 respectively respectively pair the first LED string 10 and the second LED The light string 20 performs constant current control, and the third constant current control module 5 does not perform constant current control on the LED light string; when the output voltage of the rectifier module 1 rises to be greater than the first preset voltage threshold and continues to rise and is less than the second preset voltage Threshold 吋, the serial-to-parallel conversion module 2 adjusts the output current of the first constant current control module 3, and then performs constant power control on the input power of the subsequent stage circuit; when the output voltage of the rectifier module 1 continues to rise to be greater than or equal to the second The preset voltage threshold 吋, the switching module 6 is turned on, the first constant current control module 3 and the second constant current control module 4 are turned off, and the first LED string 10 and the second LED string 20 are connected in series, the third constant Flow Control Module 5 the first LED string 10 and the second LED string 20 constant current control.

 [0073] In the embodiment of the present invention, the latter stage circuit specifically includes a serial to parallel conversion module 2, a first constant current control module 3, a second constant current control module 4, a third constant current control module 5, and a bypass module 6. The circuit portions of the first LED string 10 and the second LED string 20.

[0074] In the embodiment of the present invention, specifically, when the output voltage of the rectifier module 1 continues to rise to be greater than or equal to the second preset voltage threshold, the serial-to-parallel conversion module 2 controls the first constant current control module 3 to be turned off. Similarly, since the output voltage of the second constant current control module is greater than the first reference voltage, the second constant current control module Also in the off state.

 [0075] In the embodiment of the present invention, the voltage value of the AC power source AC may be 110V~220V, that is, the input AC voltage may vary within 110V-220V, so that the LED linear constant current driving circuit realizes the application of the wide input voltage. In the process of input voltage change, the output current of the first constant current control module 3 is adjusted by the serial-to-parallel conversion module 2, thereby adjusting the power of the first LED string 10, so that the input power of the subsequent stage circuit The LED linear constant current driving circuit provided in this embodiment has a second filter capacitor C2 connected in parallel with the output end of the rectifier module 1, so that the first LED string 10 and the second LED string 20 can be made without frequency. flash.

 6 shows a circuit configuration of an LED linear constant current driving circuit according to a third embodiment of the present invention.

[0077] As shown in FIG. 6, the circuit structure of each module in the LED linear constant current driving circuit provided by this embodiment is completely the same as the circuit structure of each module in the LED linear constant current driving circuit provided by an embodiment. For details, please refer to The related descriptions in the first embodiment corresponding to FIG. 2 and FIG. 2 are not described herein again.

[0078] The working principle of the LED linear constant current driving circuit provided by this embodiment is as follows:

[0079] As shown in FIG. 6, when the output voltage VIN of the rectifier module 1 reaches the forward conduction voltage 第一 of the first LED string 10 or the second LED string 20, the output voltage VIN of the rectifier module 1 is less than or equal to the first a preset voltage threshold, wherein the output voltage VIN of the rectifier module 1 passes through the voltage divider VT of the fourth resistor R4 and the fifth resistor R5 is less than or equal to the first reference voltage _Vre f, and the diode D1 is turned off, the first LED string 10 and the second LED string 20 are connected in parallel, the fourth switch N4 is turned off, and the voltage of the non-inverting input of the first operational amplifier EA1 is the first reference voltage Vref. Since the resistance of the third resistor R3 is smaller than the resistance of the first resistor R1, the first constant current control module 3 performs constant current control on the first LED string 10 such that the current flowing through the first LED string 10 is 11 = Vref/Rl, the third constant current control module 5 does not perform constant current control on the first LED string 10; meanwhile, the second constant current control module 4 performs constant current control on the second LED string 20, so that the flow through The current I 2 of the two LED string 20 is Vref/R2. The current flowing through the first LED string 10 and the second LED string 20 can be adjusted by adjusting the values of the first reference voltage Vref, the first resistor R1, and the second resistor R2, respectively.

[0080] When the output voltage VIN of the rectifier module 1 rises above the first preset voltage threshold and continues to rise and is less than the second predetermined voltage threshold 吋, the output voltage VIN of the rectifier module 1 passes through the fourth resistor R4 and the fifth resistor R5. The divided voltage VT is greater than the first reference voltage Vref, and the fourth switching transistor N4 is turned on. Thereafter, the series-parallel conversion module 2 starts to adjust the input voltage of the first constant current control module 3, and then flows through the first LED. String of lights 10 Current II is adjusted. Specifically, the voltage outputted by the series-parallel conversion module 2 to the non-inverting input terminal of the first operational amplifier EA1 is Vref-((VT-Vref)xR7)/R6, and the current flowing through the first LED string 10 is 11=[Vref- ((VT-Vref)xR7)/R6]/Rl = As the output voltage VIN of the rectifier module 1 increases, VT increases, and the output current II decreases, since the input power of the subsequent stage circuit is P=VIN*I1 Therefore, adjusting the size of II allows the input power of the subsequent stage circuit to remain substantially unchanged.

[0081] When the output voltage VIN of the rectifier module 1 continues to rise to be greater than or equal to the second predetermined voltage threshold 吋, the output voltage VIN of the rectifier module 1 passes through the voltage divider VT of the fourth resistor R4 and the fifth resistor R5 is greater than or equal to the first The second reference voltage VR, the comparator Compl controls the fifth switch N5 to be turned on, the first switch N1 is turned off, the first constant current drive module 3 stops working, the diode D1 is turned on, and the rectifier module 1 is adjusted. The values of the output voltage VIN, the fourth resistor R4, and the fifth resistor R5 are such that VT>VR, and the output voltage VIN of the rectifier module 1 reaches the first LED string 10 plus the turn-on voltage of the second LED string 20. Then, the first LED string 10 and the second LED string 20 are connected in series, and the third constant current control module 5 performs constant current control on the first LED string 10 and the second LE D string 20, so that the flow passes through The current I3 = V ref / R3 of the first LED string 10 and the second LED string 20. Since the resistance of the third resistor R3 is smaller than the resistance of the second resistor R2, the voltage of the low potential terminal of the second bypass transistor N2 (the non-inverting input terminal of the second operational amplifier EA2) is greater than the first reference voltage Vref, therefore, The second operational amplifier EA2 outputs a low level, the second switching transistor N2 is turned off, and the second constant current control module 4 stops operating.

 [0082] As can be seen from FIG. 9, as the output voltage VIN of the rectifier module 1 changes, the input power of the subsequent circuit remains substantially unchanged, so that the voltage of the input alternating current can be varied within a large range, and It is ensured that the input power of the latter circuit is substantially unchanged, and the first LED string 10 and the second LED string 20 can be made to achieve no stroboscopic.

 7 shows a block structure of an LED linear constant current driving circuit according to a fourth embodiment of the present invention.

[0084] As shown in FIG. 7, the LED linear constant current driving circuit provided by the embodiment of the present invention is connected to the first LED light string 10 and the second LED light string 20, and the LED linear constant current driving circuit includes the rectifier module 1 and the second The filter capacitor C2, the input end of the rectifier module 1 is connected to the AC power source AC, and the first end and the second end of the second filter capacitor C2 are respectively connected to the first output end and the second output end of the rectifier module 1, respectively, the rectifier module 1 and The second filter capacitor C 2 rectifies and filters the alternating current output from the alternating current power source AC, and outputs the direct current to supply power to the first L ED string 10 and the second LED string 20 . [0085] The LED linear constant current driving circuit further includes a serial to parallel conversion module 2, a first constant current driving module 3, a second constant current driving module 4, a third constant current driving module 5, and a switching module 6.

 [0086] The first end of the serial-to-parallel conversion module 2, the input end of the first LED light string 10, and the input end of the second constant current control module 4 are connected to the first output end of the rectifier module 1, and the serial-to-parallel conversion module 2 The second end, the output end of the first constant current driving module 3, the output end of the third constant current control module 5, and the second output end of the rectifying module 1 are connected to the ground, and the input end of the first constant current control module 3 And the output end of the first LED string 10 is connected to the input end of the switching module 6, and the voltage input end and the controlled end of the first constant current driving module 3 are respectively connected to the output end and the control end of the serial-to-parallel conversion module 2 The controlled end and the output end of the second constant current driving module 4 are respectively connected to the output end of the switching module 6 and the input end of the second LED string 20, and the output end of the second LED string 20 and the third constant current The inputs of the control module 5 are connected.

 [0087] When the output voltage of the rectifier module 1 reaches the forward conduction voltage 第一 of the first LED string 10 or the second LED string 20, the output voltage of the rectifier module 1 is less than or equal to the first preset voltage threshold, The first LED string 10 and the second LED string 20 are connected in parallel, and the first constant current control module 3 and the second constant current control module 4 respectively respectively pair the first LED string 10 and the second LED The light string 20 performs constant current control, and the third constant current control module 5 does not perform constant current control on the LED light string; when the output voltage of the rectifier module 1 rises to be greater than the first preset voltage threshold and continues to rise and is less than the second preset voltage Threshold 吋, the serial-to-parallel conversion module 2 adjusts the output current of the first constant current control module 3, and then performs constant power control on the input power of the subsequent stage circuit; when the output voltage of the rectifier module 1 continues to rise to be greater than or equal to the second The preset voltage threshold 吋, the switching module 6 is turned on, the first constant current control module 3 and the second constant current control module 4 are turned off, and the first LED string 10 and the second LED string 20 are connected in series, the third constant Flow Control Module 5 the first LED string 10 and the second LED string 20 constant current control.

 [0088] In the embodiment of the present invention, the latter stage circuit specifically includes a serial to parallel conversion module 2, a first constant current control module 3, a second constant current control module 4, a third constant current control module 5, and a gate module 6 The circuit portions of the first LED string 10 and the second LED string 20.

[0089] In the embodiment of the present invention, specifically, when the output voltage of the rectifier module 1 continues to rise to be greater than or equal to the second preset voltage threshold, the serial-to-parallel conversion module 2 controls the first constant current control module 3 to be turned off. Similarly, since the output voltage of the second constant current control module is greater than the first reference voltage, the second constant current control module is also in an off state. [0090] In the embodiment of the present invention, the voltage value of the AC power source AC may be 110V~220V, that is, the input AC voltage may vary within 110V-220V, so that the LED linear constant current driving circuit realizes the application of the wide input voltage. In the process of input voltage change, the output current of the first constant current control module 3 is adjusted by the serial-to-parallel conversion module 2, thereby adjusting the power of the first LED string 10, so that the input power of the subsequent stage circuit The LED linear constant current driving circuit provided in this embodiment has a second filter capacitor C2 connected in parallel with the output end of the rectifier module 1, so that the first LED string 10 and the second LED string 20 can be made without frequency. flash.

 8 shows a circuit configuration of an LED linear constant current driving circuit according to a fourth embodiment of the present invention.

[0092] As shown in FIG. 8, the circuit structure of each module in the LED linear constant current driving circuit provided by this embodiment is completely the same as the circuit structure of each module in the LED linear constant current driving circuit provided by an embodiment. For details, please refer to The related descriptions in the first embodiment corresponding to FIG. 2 and FIG. 2 are not described herein again.

[0093] The working principle of the LED linear constant current driving circuit provided by this embodiment is as follows:

[0094] As shown in FIG. 8, when the output voltage VIN of the rectifier module 1 reaches the forward conduction voltage 第一 of the first LED string 10 or the second LED string 20, the output voltage VIN of the rectifier module 1 is less than or equal to the first a preset voltage threshold, wherein the output voltage VIN of the rectifier module 1 passes through the voltage divider VT of the fourth resistor R4 and the fifth resistor R5 is less than or equal to the first reference voltage _Vre f, and the diode D1 is turned off, the first LED string 10 and the second LED string 20 are connected in parallel, the fourth switch N4 is turned off, and the voltage of the non-inverting input of the first operational amplifier EA1 is the first reference voltage Vref. The first constant current control module 3 performs constant current control on the first LED light string 10 such that the current flowing through the first LED light string 10 is I==Vref/Rl; meanwhile, since the resistance of the third resistor R3 is smaller than the first The resistance of the resistor R1, therefore, the second constant current control module 4 performs constant current control on the second LED string 20 such that the current flowing through the second LED string 20 is I2=Vref/R2, and the third constant current control module 5 The second LED string 20 is not subjected to constant current control. The current flowing through the first LED string 10 and the second LED string 20 can be adjusted by adjusting the values of the first reference voltage Vref, the first resistor R1, and the second resistor R2, respectively.

[0095] When the output voltage VIN of the rectifier module 1 rises above the first preset voltage threshold and continues to rise and is less than the second predetermined voltage threshold 吋, the output voltage VIN of the rectifier module 1 passes through the fourth resistor R4 and the fifth resistor R5. The divided voltage VT is greater than the first reference voltage Vref, and the fourth switching transistor N4 is turned on. Thereafter, the series-parallel conversion module 2 starts to adjust the input voltage of the first constant current control module 3, and then flows through the first LED. The current II of the string 10 is adjusted. Specifically, the serial-parallel conversion module 2 outputs the same phase to the first operational amplifier EA1. The voltage at the input is Vref-((VT-Vref)xR7)/R6, then the current flowing through the first LED string 10I=[Vref-((VT-Vref)xR7)/R6]/Rl = with rectification The output voltage VIN of module 1 increases, VT increases, and output current II decreases. Since the input power of the subsequent stage circuit is P=VIN*I1, adjusting the size of II can make the input power of the latter stage basically remain unchanged. change.

[0096] When the output voltage VIN of the rectifier module 1 continues to rise to be greater than or equal to the second predetermined voltage threshold 吋, the output voltage VIN of the rectifier module 1 passes through the voltage divider VT of the fourth resistor R4 and the fifth resistor R5 is greater than or equal to the first The second reference voltage VR, the comparator Compl controls the fifth switch N5 to be turned on, the first switch N1 is turned off, the first constant current drive module 3 stops working, the diode D1 is turned on, and the rectifier module 1 is adjusted. The values of the output voltage VIN, the fourth resistor R4, and the fifth resistor R5 are such that VT>VR, and the output voltage VIN of the rectifier module 1 reaches the first LED string 10 plus the turn-on voltage of the second LED string 20. Then, the first LED string 10 and the second LED string 20 are connected in series, and the third constant current control module 5 performs constant current control on the first LED string 10 and the second LE D string 20, so that the flow passes through The current I3 = V ref / R3 of the first LED string 10 and the second LED string 20. Since the resistance of the third resistor R3 is smaller than the resistance of the second resistor R2, the voltage of the low potential terminal of the second bypass transistor N2 (the non-inverting input terminal of the second operational amplifier EA2) is greater than the first reference voltage Vref, therefore, The second operational amplifier EA2 outputs a low level, the second switching transistor N2 is turned off, and the second constant current control module 4 stops operating.

 [0097] As can be seen from FIG. 9, as the output voltage VIN of the rectifier module 1 changes, the input power of the subsequent circuit remains substantially unchanged, so that the voltage of the input alternating current can be varied within a large range, and It is ensured that the input power of the latter circuit is substantially unchanged, and the first LED string 10 and the second LED string 20 can be made to achieve no stroboscopic.

 The embodiment of the present invention further provides an LED lighting device, which is connected to an alternating current power source and includes a first LED string and a second LED string. The LED lighting device further includes the LED linear constant provided by any of the above embodiments. Stream drive circuit.

[0099] The LED linear constant current driving circuit provided by the embodiment of the invention includes a rectifier module, a serial-to-parallel conversion module, a first constant current driving module, a second constant current driving module, a third constant current driving module, and a switching module; The output voltage of the rectifier module is less than or equal to the first preset voltage threshold 吋, the switch module is turned off, the first LED light string and the second LED light string are connected in parallel, and the first constant current control module and the second constant current control module respectively Constant current control of the first L ED string and the second LED string; when the output voltage of the rectifier module rises to be greater than the first The preset voltage threshold continues to rise and is less than the second preset voltage threshold 吋, and the serial-to-parallel conversion module adjusts the output current of the first constant current control module, thereby performing constant power control on the input power of the subsequent circuit; The output voltage continues to rise to be greater than or equal to the second predetermined voltage threshold 吋, the switching module is turned on, the first constant current control mode and the second constant current control module are turned off, the first LED string and the second LED string The series connection, the third constant current control module performs constant current control on the first LED string and the second LED string, so that the input AC voltage can be varied within a large range, and the application of the wide input voltage is realized.

 The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

Claim  [Claim 1] An LED linear constant current driving circuit is connected to a first LED light string and a second LED light string, wherein the LED linear constant current driving circuit includes a rectifying module, and the rectifying module rectifies an alternating current, and Outputting direct current power for the first LED light string and the second LED light string, wherein the LED linear constant current driving circuit further comprises a serial-to-parallel conversion module, a first constant current driving module, and a second constant a flow drive module, a third constant current drive module, and a switch module;  The first end of the serial-to-parallel conversion module, the input end of the third constant current control module, and the input end of the second constant current control module are connected to the first output end of the rectifier module, An output end of the third constant current control module is connected to an input end of the first LED light string, a second end of the serial to parallel conversion module, an output end of the first constant current driving module, and the second LED light The output end of the string and the second output end of the rectifier module are connected to the ground, and the input end of the first constant current control module and the output end of the first LED light string are connected to the switch module The input end, the voltage input end and the controlled end of the first constant current driving module are respectively connected to the output end and the control end of the serial to parallel conversion module, and the controlled end and the output end of the second constant current driving module Connecting to an output end of the switching module and an input end of the second LED string; When the output voltage of the rectifier module is less than or equal to a first preset voltage threshold 吋, the switching module is turned off, the first LED light string and the second LED light string are connected in parallel, the first constant The flow control module and the second constant current control module respectively perform constant current control on the first LED light string and the second LED light string; when the output voltage of the rectifier module rises to be greater than the first preset voltage The threshold value continues to rise and is less than the second preset voltage threshold 吋, the serial-to-parallel conversion module adjusts the output current of the first constant current control module, and then performs constant power control on the input power of the subsequent stage circuit; The output voltage of the rectifier module continues to rise to be greater than or equal to a second predetermined voltage threshold 吋, the switching module is turned on, the first constant current control mode and the second constant current control module are turned off, The first LED light string and the second LED light string are connected in series, and the third constant current control module performs constant current control on the first L ED light string and the second LED light string. The LED linear constant current driving circuit of claim 1 , wherein the first constant current control module comprises a first operational amplifier, a first switching transistor, and a first resistor; An inverting input terminal of an operational amplifier is a voltage input end of the first constant current control module, and an output end of the first operational amplifier is coupled to a control end of the first bypass transistor as the first constant current a controlled end of the control module, wherein a high potential end of the first bypass transistor is an input end of the first constant current control module, a low potential end of the first bypass transistor and a first potential of the first resistor One end is connected to the inverting input end of the first operational amplifier, and the second end of the first resistor is an output end of the first constant current control module.  The LED linear constant current driving circuit of claim 1 , wherein the second constant current driving module comprises a second operational amplifier, a second switching transistor, and a second resistor; The non-inverting input terminal and the output terminal of the second operational amplifier are respectively connected to the first reference voltage source and the control end of the second bypass transistor, and the high potential end of the second bypass transistor is the second constant current driving module The first end of the second shunt and the first end of the second resistor are connected to the inverting input end of the second operational amplifier, and the first end of the second resistor is The second ends are respectively a controlled end and an output end of the second constant current driving module.  [Claim 4] The LED linear constant current driving circuit of claim 1, wherein the third constant current driving module comprises a third operational amplifier, a third switching transistor, and a third resistor; The non-inverting input terminal and the output terminal of the three operational amplifiers are respectively connected to the first reference voltage source and the control terminal of the third bypass transistor, and the high potential terminal of the third bypass transistor is the third constant current driving module The second end of the third resistor is connected to the inverting input end of the third operational amplifier, and the second end of the third resistor is The output of the third constant current drive module. [Claim 5] The LED linear constant current driving circuit according to claim 1, wherein the serial to parallel conversion module includes a first filter capacitor, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor a fourth switch, a fifth switch, a first amplifier, a second amplifier, and a comparator, the first end of the fourth resistor and the second end of the fifth resistor are respectively the serial-to-parallel conversion module a first end and a second end, a second end of the fourth resistor, the first filter capacitor The first end of the first amplifier, the non-inverting input end of the first amplifier, and the non-inverting input end of the comparator are connected to the first end of the fifth resistor, and the second end of the first filter capacitor and the rectification a second output end of the module is connected, a control end and a high potential end of the fourth bypass tube are respectively connected to an output end of the first amplifier and a power source, and a low potential end of the fourth bypass tube is The first end of the sixth resistor is connected to the inverting input end of the first amplifier, and the second end of the sixth resistor and the first end of the seventh resistor are connected to the opposite end of the second amplifier a non-inverting input terminal of the second amplifier is connected to the first reference voltage source, and an output end of the second amplifier is connected to the second end of the seventh resistor as an output of the serial-to-parallel conversion module End, the inverting input of the comparator is connected to a second reference voltage source, and the control end and the low potential end of the fifth switch are respectively connected to an output end of the comparator and a second end of the rectifier module The output end is connected, and the high potential end of the fifth bypass tube is Serial to parallel converter control terminal module. [Claim 6] The LED linear constant current driving circuit according to claim 1, wherein the switching module is a diode;  The anode and cathode of the diode are respectively an input end and an output end of the switching module. [Claim 7] The LED linear constant current driving circuit of claim 1, wherein the LED linear constant current driving circuit further comprises a second filtering capacitor;  The first end and the second end of the second filter capacitor are respectively connected to the first output end and the second output end of the rectifier module.  [Claim 8] The LED linear constant current driving circuit according to claim 7, wherein the serial to parallel conversion module includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, and a fourth switch a tube, a fifth switch, a first amplifier, a second amplifier, and a comparator; The first end of the fourth resistor and the second end of the fifth resistor are respectively a first end and a second end of the serial to parallel conversion module, and a second end of the fourth resistor, the first end The non-inverting input terminal of the amplifier and the non-inverting input end of the comparator are connected to the first end of the fifth resistor, and the control end and the high potential end of the fourth shunt transistor are respectively connected to the output of the first amplifier The terminal is connected to the power source, the low potential end of the fourth switch and the first end of the sixth resistor are connected to the inverting input end of the first amplifier, and the second end of the sixth resistor is Said a first end of the seventh resistor is connected to the inverting input end of the second amplifier, a non-inverting input end of the second amplifier is connected to the first reference voltage source, and an output end of the second amplifier is opposite to the first The second end of the seven resistors is commonly connected as an output end of the serial to parallel conversion module, the inverting input end of the comparator is connected to a second reference voltage source, and the control end and the low potential end of the fifth bypass transistor The output end of the comparator and the second output end of the rectifier module are respectively connected, and the high potential end of the fifth switch is the control end of the serial-to-parallel conversion module. [Claim 9] An LED linear constant current driving circuit is connected to a first LED light string and a second LED light string, wherein the LED linear constant current driving circuit includes a rectifying module, and the rectifying module rectifies an alternating current, and Outputting direct current power for the first LED light string and the second LED light string, wherein the LED linear constant current driving circuit further comprises a serial-to-parallel conversion module, a first constant current driving module, and a second constant a flow drive module, a third constant current drive module, and a switch module;  The first end of the serial-to-parallel conversion module, the input end of the first LED light string, and the input end of the second constant current control module are connected to a first output end of the rectifier module, and the serial The second end of the conversion module, the output end of the first constant current driving module, the output end of the third constant current control module, and the second output end of the rectifier module are connected to the ground, the first constant The input end of the flow control module and the output end of the first LED light string are connected to the input end of the switching module, and the voltage input end and the controlled end of the first constant current driving module respectively and the string The output end of the conversion module is connected to the control end, and the controlled end and the output end of the second constant current driving module are respectively connected to the output end of the switching module and the input end of the second LED string. An output end of the second LED string is connected to an input end of the third constant current control module; When the output voltage of the rectifier module is less than or equal to a first preset voltage threshold 吋, the switching module is turned off, the first LED light string and the second LED light string are connected in parallel, the first constant The flow control module and the second constant current control module respectively perform constant current control on the first LED light string and the second LED light string; when the output voltage of the rectifier module rises to be greater than the first preset voltage The threshold value continues to rise and is less than the second preset voltage threshold 吋, the serial-to-parallel conversion module adjusts an output current of the first constant current control module, and further Performing constant power control on the input power of the subsequent circuit; when the output voltage of the rectifier module continues to rise to be greater than or equal to a second predetermined voltage threshold, the switching module is turned on, the first constant current control mode And the second constant current control module is turned off, the first LED light string and the second LED light string are connected in series, the third constant current control module is opposite to the first L ED light string and the The second LED string is subjected to constant current control. [Claim 10] An LED lighting device, connected to an alternating current power source, and including a first LED string and a second L E _D light string, wherein the LED illumination apparatus further comprises any one of claims 1-9 linear constant current LED driver circuit as claimed in claim.