CN217936004U - LED drive circuit, LED straight tube lamp and LED lamps and lanterns system compatible constant current and adjusting luminance - Google Patents

Abstract

The present application discloses an LED drive circuit compatible with constant current and dimming, an LED straight tube lamp and an LED lamp system. The LED drive circuit includes a rectification unit with an AC input terminal, a filter unit and a power conversion unit. The power conversion unit It has a detection terminal coupled to the AC input terminal, and is in two different working modes according to different input voltages of the AC input terminal, which are respectively constant output power when the input voltage of the AC input terminal is greater than the first threshold value. A streaming working mode and a dimming working mode in which the output power changes with the input voltage when the input voltage of the AC input terminal is lower than the first threshold. The LED drive circuit of the present application enters the constant current working mode and the dimming working mode according to the magnitude of the input voltage. When the input voltage is less than the first threshold, it meets the brightness adjustment requirements; when the input voltage is greater than the first threshold, it meets the maintenance lighting requirements. brightness requirements.

Description

Compatible with constant current and dimming LED drive circuits, LED straight tube lamps and LED lighting systems

technical field

The present application relates to the technical field of illumination, in particular to an LED driving circuit compatible with constant current and dimming, LED straight tube lamp and LED lamp system.

Background technique

LED lighting technology is rapidly developing to replace traditional incandescent and fluorescent lamps. With the advantages of energy saving, low energy consumption, environmental protection and long life of LED lamp tubes, LED straight tube lamps have gradually become a highly anticipated lighting option without accident. Therefore, after considering all factors, LED straight tube lights will be a cost-saving and long-life green lighting option.

Traditional fluorescent lamps generally include electronic ballasts, fluorescent tubes, and lamp carriers. In order to achieve energy saving, environmental protection and long life, improve ordinary fluorescent lamps, make them more energy-saving and environmentally friendly, improve their luminous efficiency, and prolong their service life, it is necessary to replace traditional fluorescent lamps with LED lamps. There are two options for replacing fluorescent lamps with LED lamps: the first is the TYPE A replacement type, where the fluorescent lamps are directly removed and replaced with LED lamps without any modifications to the wiring. The second is to bypass the ballast by cutting the wire, and realize single-end or double-end power supply through wiring, that is, TYPE B wire-cutting type. In addition, there is also a TYPE A+B dual-function switching compatible type that is compatible with both.

Utility model content

Based on this, it is necessary to provide an LED drive circuit compatible with constant current and dimming, an LED straight tube lamp and an LED lighting system for the above technical problems.

The present application provides an LED drive circuit compatible with constant current and dimming, including a rectification unit with an AC input terminal, a filter unit and a power conversion unit, the power conversion unit has a detection terminal coupled to the AC input terminal, and according to Different input voltages at the AC input end are in two different working modes, namely, the constant current operating mode in which the output power remains constant when the input voltage at the AC input end is greater than the first threshold value, and the constant current operating mode at which the input voltage at the AC input end is less than the first threshold value. A dimming working mode in which the output power varies with the input voltage at the threshold.

The following also provides several optional ways, but they are not used as additional limitations on the above-mentioned overall scheme, but are only further additions or optimizations. On the premise of no technical or logical contradiction, each optional way can be carried out independently for the above-mentioned overall scheme Combination can also be a combination of multiple options.

Optionally, the power conversion unit includes a switch tube, the switch tube has a gate, a source and a drain, the drain is coupled to the load via an inductance element, and the source is grounded via a sampling circuit ;

In the constant current working mode, the conduction angle of the switch tube decreases as the input voltage increases;

In the dimming working mode, the conduction angle of the switch tube is at a maximum value and remains unchanged.

Optionally, the power conversion unit includes:

a driver, coupled to the gate;

an impedance detector, the input end of which is coupled to the detection end;

The comparison controller has a sampling input terminal and a control output terminal, the sampling input terminal is coupled to the output terminal of the impedance detector, and the control output terminal is coupled to the input terminal of the driver.

Optionally, the power conversion unit includes a main control chip and peripheral circuits, and the switch tube, driver, impedance detector and comparison controller are integrated in the main control chip.

Optionally, the first threshold is between 108V and 120V.

Optionally, a voltage detection unit coupled between the AC input terminal and the detection terminal is included, and the voltage detection unit includes:

a first diode, the anode of which is coupled to the AC input terminal;

One end of the first resistor is coupled to the cathode of the first diode, and the other end is coupled to the detection end.

Optionally, the rectification unit includes a first rectification unit and a second rectification unit, the first rectification unit has a first AC input terminal and a second AC input terminal, and the first AC input terminal and/or the second AC input terminal The AC input end is coupled to the detection end through the voltage detection unit.

Optionally, the second rectification unit has a third AC input terminal and a fourth AC input terminal, and the LED driving circuit includes a frequency detection circuit coupled to the third AC input terminal, the fourth AC input terminal and a load .

The present application also provides an LED straight tube lamp, which includes a lamp housing composed of a lamp tube and end caps at both ends. The lamp housing is provided with a light-emitting component and a driving power supply. An LED driving circuit, the end cover is provided with a conductive member coupled with the AC input end.

The present application also provides an LED lamp system, including the LED straight tube lamp as described in the present application and a dimmer, the dimmer is coupled to the conductive member and used to adjust the input voltage.

The LED drive circuit compatible with constant current and dimming of the present application has at least the following technical effects:

The LED drive circuit compatible with constant current and dimming in this application enters the constant current working mode and dimming working mode according to the size of the input voltage. When the input voltage is less than the first threshold, it can meet the brightness adjustment requirements; when the input voltage is greater than the first threshold In the case of threshold value, the requirement of maintaining the brightness of the lighting is met.

Description of drawings

FIG. 1 is a schematic structural view of an LED straight tube lamp in an embodiment of the present application;

Fig. 2 is a schematic circuit diagram of a rectification unit in an embodiment of the present application;

FIG. 3 is a circuit schematic diagram of a frequency detection circuit in an embodiment of the present application;

FIG. 4 is a schematic structural diagram of an LED lamp system in an embodiment of the present application;

5 is a schematic diagram of a module structure of an LED driving circuit in an embodiment of the present application;

FIG. 6 is a structural block diagram of the main control chip in an embodiment of the present application;

FIG. 7 is a circuit schematic diagram of a rectification unit and a voltage detection unit in an embodiment of the present application;

FIG. 8 is a schematic circuit diagram of a power conversion unit in an embodiment of the present application;

FIG. 9 is a circuit schematic diagram of an LED driving circuit in an embodiment of the present application;

Fig. 10 is a working principle diagram of a dimmer in an embodiment of the present application;

Fig. 11 is a working principle diagram of a dimmer in an embodiment of the present application;

The reference signs in the figure are explained as follows:

100, lamp shell; 101, lamp tube; 102, end cover; 110, conductive member; 111, first pin; 112, second pin; 113, third pin; 114, fourth pin; 120, Ballast;

200, rectification unit; 210, first rectification unit; 220, second rectification unit; 300, filter unit;

400. Power conversion unit; 410. Main control chip; 411. Impedance detector; 412. Comparison controller; 413. Driver; 414. Switch tube; 420. Secondary filter unit;

500, a frequency detection circuit; 600, a dimmer; 700, a voltage detection unit.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the application with reference to the drawings in the embodiments of the application. Apparently, the described embodiments are only some, not all, embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

It should be noted that when a component is referred to as being "coupled" to another component, it can be directly connected to the other component or intervening components may also exist. When a component is said to be "set on" another component, it may be set directly on the other component or there may be an intervening component at the same time.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the description of the application are only for the purpose of describing specific embodiments, and are not intended to limit the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the present application, the terms "first", "second" and so on are only used for descriptive purposes, and should not be understood as indicating or implying relative importance or implicitly indicating the quantity and order of the indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In this application, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a system, product or device comprising a series of elements is not necessarily limited to those elements explicitly listed, but may include other units not expressly listed or inherent to those products or equipment.

Referring to Fig. 1 and Fig. 2, an embodiment of the present application provides an LED straight tube lamp, which includes a lamp housing 100 composed of a lamp tube 101 and end caps 102 at both ends, and a light-emitting component and a driving power supply are arranged inside the lamp housing 100 , the driving power supply is provided with an LED driving circuit, and the end cover 102 is provided with a conductive member 110 coupled to the AC input terminal. The conductive member 110 includes a first pin 111 and a second pin 112 provided on one end cover 102, and a third pin 113 and a fourth pin 114 provided on the other end cover 102, wherein the third pin 113 and the fourth pin 114 are shorted.

The LED drive circuit includes a rectification unit 200 with an AC input terminal, a filter unit, and a power conversion unit. The rectification unit 200 includes a first rectification unit 210 and a second rectification unit 220. The first rectification unit 210 may be, for example, a rectification bridge BD1, and the second rectification unit The rectification unit 220 may be, for example, a rectification bridge BD2. The rectifier unit 200 outputs a DC bus Vbus+, and a piezoresistor RV1 is connected between the DC bus Vbus+ and the ground.

The AC input terminals specifically include the first AC input terminal L1 and the second AC input terminal N1 of the first rectification unit 210 , and the third AC input terminal AC2 and fourth AC input terminal AC3 of the second rectification unit 220 . Wherein, the third AC input terminal AC2 and the fourth AC input terminal AC3 are short-circuited and coupled to the short-circuited third pin 113 and fourth pin 114 via the fuse F3, and the fuse F3 is used to monitor the voltage of the piezoresistor RV1 In working state, protect against abnormal state. A capacitor CX1 is coupled between the first AC input terminal L1 and the second AC input terminal N1, a capacitor CX2 is coupled between the third AC input terminal AC2 and the second AC input terminal N1, and the capacitor CX1 and the capacitor CX2 form a step-down voltage. Protect.

Referring to FIG. 3 , the LED driving circuit includes a frequency detection circuit 500 coupled between a load and a third AC input terminal AC2 and a fourth AC input terminal AC3. The load may be, for example, a light-emitting component. The frequency detection circuit 500 specifically includes a circuit topology composed of a capacitor C8, a capacitor C9, a diode D6, a diode D7, a Zener diode Z1, a resistor R15, and a switch tube Q1, which are used to determine the conversion between the mains mode and the ballast mode, The switch tube may be, for example, a MOSFET tube. The mains mode means the input voltage is 120-277V and the frequency is 50-60Hz; the ballast mode means the input voltage is 800-1200V and the frequency is 25K-80KHz.

In the TYPE A replacement working mode, the conductive elements 110 at both ends of the lamp housing 100 are coupled to the ballast 120, and the frequency detection circuit 500 passes through the third AC input terminal AC2 and the fourth AC input terminal AC3, specifically HIF in the figure The pin receives the AC signal, the high-frequency 25K-100KHz high-frequency AC enters through each AC input terminal, the frequency detection circuit 500 enters the working state, the capacitor C8 performs high-frequency voltage and current sampling, and the diode D6 and diode D7 rectify and filter, so that the switch tube Q1 conducts Through the Q1-D pin in the figure, that is, the drain of the switch tube Q1 is coupled to the load to supply power to the load. In TYPE A mode, as long as the ballast 120 itself has the dimming function, the fluorescent tube can be directly replaced with an LED straight tube lamp to realize dimming, such as thyristor dimming, 0-10V dimming, etc., to achieve energy saving and environmental protection Function, in line with DLC5.1 requirements.

In the mains mode, the industrial power voltage is 277V, and the household power voltage is 120V. In household use, dimmers are usually used to adjust the brightness of lamps. At the same time, there is a need to maintain the brightness when the voltage fluctuates and changes, and there is a need to maintain the brightness of the lamps under industrial power consumption.

Referring to FIG. 4 and FIG. 5 , in one embodiment, an LED lighting system is provided, including a dimmer 600 and the LED straight tube lamp in the previous embodiment. The dimmer 600 is coupled to the conductive member 110 for To adjust the input voltage, the dimmer 600 can adjust the input voltage AC by, for example, a leading-cut or trailing-cut method.

In this embodiment, the LED driving circuit is compatible with constant current and dimming, and includes a rectifier unit 200 with an AC input terminal, a filter unit 300, and a power conversion unit 400. The power conversion unit 400 has a detection terminal DET coupled to the AC input terminal, and according to the AC Different input voltages at the input end are in two different working modes, respectively, the constant current operating mode in which the output power remains constant when the input voltage at the AC input end is greater than the first threshold value and the input voltage at the AC input end is less than the first threshold value The dimming working mode in which the output power changes with the input voltage. The first threshold is between 108-120V, for example, 110V, so as to avoid dimming fluctuations due to voltage fluctuations. It can be understood that in the TYPE B mode, the power conversion unit 400 works normally, realizes the constant current mode and the dimming mode, realizes the advantages of multiple functions, and complies with the requirements of UL safety regulations and DLC5.1.

5 and 6, the power conversion unit 400 includes a switching tube 414, the switching tube 414 has a gate, a source and a drain, the drain of the switching tube 414 is coupled to the load via an inductive reactance element, and the source is coupled to the load via a sampling circuit ground. The inductive reactance element can be, for example, a transformer or an inductor, and the sampling circuit can be, for example, a sampling resistor RS. In the constant current mode, the conduction angle of the switch tube 414 decreases as the input voltage increases; in the dimming mode, the conduction angle of the switch tube 414 is at a maximum value and remains unchanged.

In this embodiment, the power conversion unit 400 includes an impedance detector 411 , a comparison controller 412 , a driver 413 , and a switch tube 414 . The input end of the impedance detector 411 is coupled to the detection end DET. The comparison controller 412 has a sampling input terminal and a control output terminal, wherein the sampling input terminal is coupled to the output terminal of the impedance detector 411 , and the control output terminal is coupled to the input terminal of the driver 413 . The output terminal of the driver 413 is coupled to the gate of the switch transistor 414 for adjusting the conduction angle of the switch transistor 414 . The power conversion unit 400 includes a main control chip 410 and peripheral circuits. A switch tube 414 , a driver 413 , an impedance detector 411 and a comparison controller 412 are integrated in the main control chip 410 . The drain of the switch tube 414 is specifically the output terminal Dra of the main control chip, and the source is specifically the sampling terminal ISP of the main control chip.

In this embodiment, the switching between the constant current mode and the dimming mode can be realized by adaptively driving the switch tube, which can meet the requirements of stable lighting brightness in the factory and dimming of the household lighting at the same time. Moreover, different circuit components are controlled and driven by using the characteristics of a switch tube itself instead of logic judgment, which reduces the use of circuit components, simplifies the control mode, and ensures control stability.

In the constant current working mode, the conduction angle changes adaptively between 1 degree and 360 degrees, keeping the output power unchanged. Of course, limited by the limitation of the switch tube itself, the range of adaptive change of the conduction angle is limited, for example, the adjustable period of the conduction time of the switch tube is 0.9-11 μs. In the dimming working mode, the conduction angle of the switching tube reaches the limit state, and cannot be adaptively changed. Exit from the constant current working mode and enter the dimming working mode. At this time, the output power of the power conversion unit is only affected by the external input voltage .

An example is as follows: in the initial state, the input voltage may be 277V, for example. When the input voltage drops from 277V, the conduction angle of the switch tube 414 gradually increases to keep the output power constant. When the input voltage reaches the first threshold, for example 110V, the conduction angle of the switch tube 414 reaches the maximum adjustable value. As the input voltage continues to drop from 110V, the output power begins to drop with it.

In this embodiment, the detection terminal DET detects the input voltage of the AC input terminal, and the impedance detector 411 samples the input current and voltage through an internal sampling resistor to obtain a detection result, which is generally proportionally reduced relative to the input voltage of the AC input terminal. The comparison controller 412 has a reference voltage, for example, 200mV. The comparison controller 412 compares the detection result with the reference voltage, and controls the driver 413 to adjust the conduction angle of the switch tube 414 according to the comparison result. The comparison controller 412 can realize its function through an operational amplifier, for example, and the driver 413 can control the PWM signal correspondingly to the comparison controller 412 to complete the gate drive control. Furthermore, the grounded source via a sampling circuit is also coupled to the comparison controller 412 to form output feedback control and ensure control accuracy.

Referring to FIG. 7 , the LED driving circuit further includes a voltage detection unit 700 coupled between the AC input terminal and the detection terminal DET, and the voltage detection unit 700 includes a first diode D1 and a first resistor R1. Wherein, the anode of the first diode D1 is coupled to the AC input terminal; one end of the first resistor R1 is coupled to the cathode of the first diode D1, and the other end is coupled to the detection terminal DET.

Further, the first AC input terminal L1 and/or the second AC input terminal N1 are coupled to the detection terminal DET through the voltage detection unit 700 . When the LED drive circuit is built into the LED straight tube lamp provided by each embodiment, the detection of the input voltage can be realized regardless of single-end power supply or double-terminal power supply. Specifically, the voltage detection unit disposed between the second AC input terminal N1 and the detection terminal DET includes a diode D2 and a resistor R2. Wherein, the anode of the diode D2 is coupled to the second AC input terminal N1, one end of the resistor R2 is coupled to the cathode of the diode D2, and the other end is coupled to the detection terminal DET.

Referring to FIG. 3 , and FIG. 6 to FIG. 8 , the filter unit 300 and the power conversion unit 400 can be arranged as shown in the figure. The filtering unit 300 includes an EMI anti-interference circuit, including an inductor L1, a capacitor C1 and a capacitor C2. The main control chip 410 included in the power conversion unit 400 has a power input terminal VIN, a power supply terminal VCC, an output terminal Dra, a ground terminal GND, a sampling terminal ISP, and a detection terminal REC. Wherein, the power input terminal VIN is coupled to the DC bus Vbus+ via the resistor R8. The power supply terminal VCC is coupled to the power input terminal VIN to provide the working voltage of the chip, and is grounded through the capacitor C3, which is charged when in use. The output terminal Dra is coupled to the drain of the built-in switch 414 . The sampling terminal ISP is grounded via a resistor RS1 and a resistor RS2. The detection terminal REC is coupled to the detection terminal DET. The output terminal Dra is coupled to the load via the transformer T1, and only the input terminal V1+ and the output terminal V1- of the load are shown in the figure. A secondary filter unit 420 is provided between the input terminal V1+ and the output terminal V1- of the load, including a topology circuit composed of capacitor CD1, capacitor CD2 and resistor R14. In each embodiment, the internal or peripheral circuit of the main control chip is also provided with a leakage detection circuit. If the leakage detection circuit detects a risk of electric shock, it will disconnect the entire circuit, reducing the risk of use and potential safety hazards. The detailed content and working principle of the leakage protection circuit will not be repeated here, and reference may be made to the prior art.

This embodiment is compatible with TYPE A and TYPE B working modes. In the TYPE A mode, the frequency detection circuit 500 enters the working state, the AC input terminal is rectified by the diode D6 and the diode D7, and the switch tube Q1 is coupled to the secondary filter unit 420 through the Q1-D pin to supply power to the load. The main control chip stops working. In TYPE B mode, the low-frequency AC50-60Hz AC is powered through the AC input terminal, and the switch tube Q1 does not work. The alternating current passes through the rectifying unit 200 , the filtering unit 300 and the power conversion unit in sequence to complete the selection of the constant current working mode and the dimming working mode.

The LED straight tube lamp and the LED drive circuit provided in each embodiment of the present application are TYPE A+B dual-function conversion compatible type. High luminous efficiency, all with dimming function. In TYPE B mode, it can realize the adaptive adjustment of constant current working mode and dimming working mode according to the input voltage.

Referring to FIGS. 9 to 11 , in one embodiment, an LED drive circuit as shown in the figure is provided. The LED drive circuit includes a rectification unit BD and a power conversion unit PC coupled sequentially. The rectification unit BD may be, for example, a full-wave rectification bridge. It has an AC input terminal and a DC output terminal. The AC input terminal of the rectifier unit BD is coupled to the mains through a dimmer TRIAC Dimmer. The mains can be, for example, AC120V/60Hz. The principle or the front-cutting principle in Fig. 11 is realized.

The DC output end is provided with a filter capacitor, and the power conversion unit PC includes a main control chip 410 and its peripheral circuits. In this embodiment, the connection modes of the power supply terminal VCC, the power input terminal VIN, the ground terminal GND, the sampling terminal ISP, and the detection terminal REC of the main control chip 410 can be referred to in the above embodiments. The output terminal Dra of the main control chip 410 is coupled to the load, that is, the light emitting diode Dx via an inductor.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification. When the technical features in different embodiments are embodied in the same drawing, it can be considered that the drawing also discloses the combination examples of the various embodiments involved.

The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is relatively specific and detailed, but should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims (10)

1. The LED driving circuit compatible with constant current and dimming comprises a rectifying unit with an alternating current input end, a filtering unit and a power conversion unit, and is characterized in that the power conversion unit is provided with a detection end coupled with the alternating current input end, and is in two different working modes according to different input voltages of the alternating current input end, namely a constant current working mode in which the output power of the constant current working mode is kept constant when the input voltage of the alternating current input end is greater than a first threshold value and a dimming working mode in which the output power of the constant current working mode changes along with the input voltage when the input voltage of the alternating current input end is less than the first threshold value.

2. The LED driving circuit of claim 1, wherein the power conversion unit comprises a switch tube having a gate, a source and a drain, the drain being coupled to a load via an inductive reactance element, the source being grounded via a sampling circuit;

in the constant-current working mode, the conduction angle of the switch tube is reduced along with the increase of the input voltage;

and in the dimming working mode, the conduction angle of the switch tube is at the maximum value and is kept unchanged.

3. The LED driving circuit according to claim 2, wherein the power conversion unit comprises:

a driver coupled to the gate;

an impedance detector having an input terminal coupled to the detection terminal;

a comparison controller having a sampling input coupled to the output of the impedance detector and a control output coupled to the input of the driver.

4. The LED driving circuit according to claim 3, wherein the power conversion unit comprises a main control chip and a peripheral circuit, and the switching tube, the driver, the impedance detector and the comparison controller are integrated in the main control chip.

5. The LED driving circuit of claim 1, wherein the first threshold is between 108-120V.

6. The LED driving circuit according to claim 1, comprising a voltage detection unit coupled between the ac input terminal and the detection terminal, the voltage detection unit comprising:

a first diode, the anode of which is coupled to the alternating current input end;

and one end of the first resistor is coupled to the cathode of the first diode, and the other end of the first resistor is coupled to the detection end.

7. The LED driving circuit according to claim 6, wherein the rectifying unit comprises a first rectifying unit and a second rectifying unit, the first rectifying unit has a first AC input end and a second AC input end, and the first AC input end and/or the second AC input end is coupled to the detecting end through a voltage detecting unit.

8. The LED driving circuit according to claim 7, wherein the second rectifying unit has a third AC input terminal and a fourth AC input terminal, the LED driving circuit comprising a frequency detection circuit coupled to the third AC input terminal, the fourth AC input terminal and a load.

The LED straight lamp comprises a lamp shell consisting of a lamp tube and end covers at two ends of the lamp tube, wherein a light-emitting component and a driving power supply are arranged in the lamp shell, and the LED straight lamp is characterized in that the driving power supply is provided with an LED driving circuit according to any one of claims 1-8, and the end covers are provided with conductive pieces coupled with the alternating current input end.

An LED lamp system comprising the LED straight tube lamp of claim 9 and a dimmer coupled to the conductive member for regulating the input voltage.

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