CN103957631B - A kind of LED drive chip, LED drive circuit and LED lamp - Google Patents

Abstract

The invention belongs to the field of LED lighting, and in particular relates to an LED driving chip, an LED driving circuit and an LED lamp. The LED drive chip provided by the present invention is connected to the rectifier bridge and the LED lamp group, and specifically includes a switch control module, a voltage adjustment module and a load; wherein, the switch control module and the LED lamp group are jointly connected to the output end of the rectifier bridge, and the switch control module The ground terminal, the output terminal of the switch tube and the DC input terminal of the rectifier bridge are connected to the ground together, and the input terminal and the controlled terminal of the switch tube are respectively connected to the output terminal of the LED lamp group and the control terminal of the switch control module; the voltage adjustment module is connected to the switch tube input and load. Since the voltage adjustment module supplies power to the load by adjusting the voltage at the input terminal of the switch tube, the LED drive circuit is applied to the LED lamp, which significantly improves the working efficiency of the LED lamp.

Description

A kind of LED driving chip, LED driving circuit and LED lamp

technical field

The invention belongs to the field of LED lighting, and in particular relates to an LED driving chip, an LED driving circuit and an LED lamp.

Background technique

With the advantages of high efficiency, high integration and long life, LED lamps are more and more widely used in the lighting field. In LED lamps, due to the requirements for integration and manufacturing costs, AC LED drive schemes without inductance and capacitors and other energy storage devices account for an increasing share of the market, and will definitely become the mainstream in the future. This type of driving scheme is to adjust the number of actually working LED lamp groups by controlling the on-off of the switch tube through the control chip, so as to achieve the purpose of limiting the current flowing through the LED lamp groups.

However, in this type of LED driving scheme, the power supply of the driver chip is mostly rectified AC mains, and the loads such as the dimming module and the lighting system control module need to convert the high-voltage direct current into the required low-voltage through a high-voltage regulator. Direct current, this will not only reduce the efficiency of the system, but also increase the additional manufacturing cost of LED lamps, thereby limiting the application and promotion of this type of driving scheme.

Therefore, the existing LED lamps using an AC LED driving scheme have the problem of low system efficiency.

Contents of the invention

The purpose of the present invention is to provide an LED driver chip, aiming at solving the problem of low system efficiency in the existing LED lamps using an AC LED driver scheme.

The present invention is achieved in this way, an LED driver chip is connected to a rectifier bridge and a first LED lamp group, the LED driver chip includes a switch control module, a first switch tube and a load; the rectifier bridge is connected to an alternating current, and The alternating current is rectified and output to the switch control module and the first LED lamp group, the input end of the first switch tube is connected to the output end of the first LED lamp group, and the switch control module controls The switching frequency of the first switching tube is used to adjust the current flowing through the first LED lamp group;

The LED driver chip also includes a first voltage adjustment module;

The power supply terminal and the output terminal of the first voltage adjustment module are respectively connected to the input terminal of the first switch tube and the power supply terminal of the load;

The first voltage adjustment module connects the output end of the first LED lamp group to direct current, performs voltage conversion processing on the direct current, and supplies power to the load.

Another object of the present invention is to provide an LED driving circuit, which includes a rectifier bridge and the above-mentioned LED driving chip.

Another object of the present invention is to provide an LED lamp, which includes a casing and the above-mentioned LED driving circuit.

The LED drive chip provided by the present invention is connected to the rectifier bridge and the first LED lamp group, and specifically includes a switch control module, a first voltage adjustment module, a load, and a first voltage adjustment module; After rectification, the output is sent to the switch control module and the first LED lamp group. The input end of the first switch tube is connected to the output end of the first LED lamp group. The switch control module controls the switching frequency of the first switch tube to adjust the flow through the first LED lamp. The current of the lamp group; the power supply terminal and the output terminal of the first voltage adjustment module are respectively connected to the input terminal of the first switching tube and the power supply terminal of the load; After the voltage conversion process, it supplies power to the load. Since the first voltage adjustment module supplies power to the load by adjusting the voltage at the output end of the first LED lamp group, it has higher efficiency than directly adjusting the voltage output by the rectifier bridge. Applying the LED drive circuit to LED lamps significantly improves the working efficiency of the LED lamps.

Description of drawings

Fig. 1 is the block diagram of the first embodiment of the LED driver chip provided by the present invention;

Fig. 2 is an example circuit structure diagram of the first voltage adjustment module of the first embodiment of the LED driver chip provided by the present invention;

Fig. 3 is a module structure diagram of the second embodiment of the LED driver chip provided by the present invention;

FIG. 4 is a comparison diagram of the voltage variation curve at the output end of the rectifier bridge and the voltage variation curve at the drain of the switch tube in the second embodiment of the LED driver chip provided by the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The LED drive chip provided by the present invention is connected to the rectifier bridge and the first LED lamp group, and specifically includes a switch control module, a first voltage adjustment module and a load; it solves the problem of low system efficiency in existing LED lamps that adopt an AC LED drive scheme question.

Example 1

Fig. 1 shows the module structure of the LED driver chip provided by the present invention, for ease of explanation, only shows the part relevant to the present invention, detailed description is as follows:

The LED driver chip provided in this embodiment is connected to the rectifier bridge 10 and the first LED lamp group 30 , and may include a switch control module 20 , a first switch tube 40 and a load 60 .

Specifically, the power supply terminal of the switch control module 20 and the input terminal of the first LED lamp group 30 are connected to the output terminal of the rectifier bridge 10, the ground terminal of the switch control module 20, the output terminal of the first switch tube 40 and the rectifier bridge 10 The DC input ends of the first switch tube 40 are connected to the ground, and the input end and the controlled end of the first switch tube 40 are respectively connected to the output end of the first LED lamp group 30 and the first control end of the switch control module 20 .

Wherein, the AC input end of the rectifier bridge 10 is connected to the AC mains, and the switch control module 20 controls the switching frequency of the first switch tube 40 to adjust the current flowing through the first LED lamp group 30 .

Further, the LED driver chip also includes a first voltage adjustment module 50;

The power supply terminal and the output terminal of the first voltage adjustment module 50 are respectively connected to the input terminal of the first switch tube 40 and the power supply terminal of the load 60 .

The first voltage adjustment module 50 receives direct current from the output end of the first LED lamp group 30 , and performs voltage conversion on the direct current to supply power to the load 60 .

Since the first voltage adjustment module 50 supplies power to the load 60 by adjusting the voltage of the output terminal of the first LED lamp group 30 , it has higher efficiency than the method of directly adjusting the voltage output by the rectifier bridge 10 .

Further, the enable terminal of the first voltage adjustment module 50 is connected to the first enable signal output terminal of the switch control module 20 . A technician can control the first voltage adjustment module 50 to be turned on and off through the switch control module 20 .

In this embodiment, as shown in FIG. 2, the first voltage adjustment module 50 may include:

N-type JFET tube Q1, first NMOS tube Q2, second NMOS tube Q3, third NMOS tube Q4, first resistor R1, second resistor R2, third resistor R3, capacitor C1, and regulator tube D1;

The drain of the N-type JFET Q1 is the input terminal of the first voltage adjustment module, the first end of the first resistor R1 and the first end of the second resistor R2 are connected to the source of the N-type JFET Q1, and the second The gate of an NMOS transistor Q2 is the enabling terminal of the first voltage adjustment module, the drain of the first NMOS transistor Q2, the gate of the second NMOS transistor Q3, the drain of the second NMOS transistor Q3, the first resistor R1 The second end and the first end of the capacitor C1 are jointly connected to the controlled end of the third NMOS transistor Q4, the second end of the second resistor R2 is connected to the drain of the third NMOS transistor Q4, and the source of the second NMOS transistor Q3 is connected to The first terminal of the third resistor R3, the second terminal of the third resistor R3 is connected to the cathode of the regulator tube D1, the source of the third NMOS tube Q4 is the output terminal of the first voltage adjustment module, and the gate of the N-type JFET tube Q1 The pole, the source of the first NMOS transistor Q2, the substrate of the first NMOS transistor Q2, the substrate of the second NMOS transistor Q3, the substrate of the third NMOS transistor Q4, and the anode of the regulator transistor D1 are commonly connected to ground.

In this embodiment, the switch control module 20 may be an 80C51 single-chip microcomputer chip with a voltage stabilizing module, or it may be other signal sources capable of outputting square wave signals. The rectifier bridge 10 can use an existing rectifier chip, and the model can be MB6S. The first switch tube 40 may be an NMOS tube, wherein the drain, the source and the gate of the NMOS tube are respectively the input end, the output end and the controlled end of the first switch tube 40 . The first switch tube 40 may also be a JFET tube, a triode, or the like.

Further, the LED driver chip further includes a first current diversion module 70 connected in series between the first voltage adjustment module 50 and the load 60;

The input terminal and the output terminal of the first current diversion module 70 are respectively connected to the output terminal of the first voltage adjustment module 50 and the power supply terminal of the load 60 .

In this embodiment, by adding the first current diversion module 70, the current output by the first voltage adjustment module 50 can flow in one direction, and at the same time, the load 60 can be prevented from damaging the front-end module due to failure or the like.

Specifically, the first diversion module 70 may use a diode, and the anode and cathode of the diode are the input end and the output end of the first diversion module 70 respectively. The first diversion module 70 may also be a network composed of triodes and resistors, the structure of which belongs to the prior art, and will not be repeated here.

Example 2

The implementation of this embodiment is based on the previous embodiment.

Fig. 3 shows the module structure of the LED driver chip provided by this embodiment, for the convenience of explanation, only shows the part related to this embodiment, the details are as follows:

In this embodiment, the LED driver chip is also connected to one or more second LED lamp groups 31, the LED driver chip also includes one or more second switch tubes 41, and the switch control module 20 also has one or more second Control terminal.

Moreover, the number of one or more second switch transistors 41 , the number of one or more second switch transistors 41 and the number of one or more second control terminals are equal.

Specifically, one or more second LED lamp groups 31 start from the output end of the first LED lamp group 30 and are sequentially connected in series in a manner of connecting the input end to the output end.

The controlled terminals of each of the one or more second switch transistors 41 are connected to each of the one or more second control terminals in one-to-one correspondence.

The input end of each second switching tube 41 is connected to the output end of each second LED lamp group 31 in one or more second LED lamp groups 31 in one-to-one correspondence;

The output terminal of each second switch tube 41 is commonly connected to the ground terminal of the switch control module 20 .

In this embodiment, the LED driver chip is actually an extension of the LED driver chip provided in Embodiment 1, which has multiple LED lamp groups, has higher power, and has a wider application range. At the same time, it has the same first voltage adjustment module 50 as the LED driver chip provided in the embodiment, which can provide one power output to supply power for the first auxiliary load.

Further, the LED driver chip may also include one or more second voltage adjustment modules 51 .

Moreover, the number of one or more second voltage adjustment modules 51 is equal to the number of one or more second switch tubes 41 .

Specifically, the power supply terminal of each second voltage adjustment module 51 in one or more second voltage adjustment modules 51 is connected to the input end of each second switching tube 41 in one-to-one correspondence, and each second voltage adjustment module 51 The output terminal of the load 70 is connected to the power supply terminal.

In this embodiment, the LED driver chip increases the number of voltage adjustment modules and multi-channel power output to ensure the power demand of the load 70 .

Further, the switch control module 20 also has one or more second enable signal output terminals;

The number of one or more second enable signal output terminals is equal to the number of one or more second voltage adjustment modules 51;

The enabling terminals of each second voltage adjustment module 51 are connected to each of the one or more second enabling signal output terminals in a one-to-one correspondence.

In this embodiment, technicians can control the first voltage adjustment module 50 and the second voltage adjustment module 51 to be turned on and off through the switch control module 20 , so as to select a voltage adjustment module with the most suitable output voltage to supply power to the load 70 .

Further, the LED driver chip may also include one or more second drainage modules 71;

The number of one or more second diversion modules 71 is equal to the number of one or more second voltage adjustment modules 51;

Each of the one or more second current diversion modules 71 is connected in series between each second voltage adjustment module 51 and the load 60 in a one-to-one correspondence;

The input terminals of each second current diversion module 71 are connected to the output terminals of each second voltage adjustment module 51 in one-to-one correspondence, and the output terminals of each second current diversion module 71 are commonly connected to the power supply terminal of the load 60 .

In this embodiment, the second drainage module 71 may adopt the same structure as the first drainage module 70 , and its function is also the same as that of the first drainage module 70 .

The working principle of the LED driver chip provided by the present invention is further described below in conjunction with FIG. 4:

Taking the LED driver chip including 4 NMOS tubes and matching with 4 sets of LED lights as an example, the 4 NMOS tubes are denoted as the first NMOS tube, the second NMOS tube, the third NMOS tube and the fourth NMOS tube. The connected AC mains is connected to the switch control module 20 and the LED lamp group after passing through the rectifier bridge 10 . As shown in Figure 4. Among them, curve a is the voltage change curve Vin of the rectifier bridge 10 in one cycle after rectification of the connected AC mains, and curve b is the switch tube drain voltage conversion curve Vdr of the current flowing through the LED lamp group on the NMOS tube . The four NMOS transistors will be turned on and off according to the logic of the switch control module, and it is guaranteed that only one voltage adjustment module is in the working state through the enable control within one cycle. This part belongs to the prior art, and its specific principles will not be repeated.

For curve b, interval tr1 and interval tf1 represent the waveform of the drain of the first NMOS transistor, interval tr2 and interval tf2 represent the waveform of the drain of the second NMOS transistor, interval tr3 and interval tf3 represent the waveform of the drain of the third NMOS transistor, interval tr4 and interval tf4 represent the waveform of the drain of the fourth NMOS transistor. According to the selected LED lamp group and the model of the NMOS tube, the drain of the NMOS tube after power-on can provide a voltage of 0-60V, and the effective voltage is about 30V.

The drain of the NMOS transistor is connected to the power supply terminal of the voltage regulator, and the voltage on the drain is converted by the voltage regulator to obtain another voltage. In this way, the required lower voltage can be obtained without converting the high-voltage power supply. For SoC or other modules.

Assuming that a 5V low-voltage power supply is required, the conversion efficiency of the traditional solution to the connected AC mains is: η1≈5/220=2.27%; while the conversion efficiency of this application solution is: η2≈5/30=16.67 %, it can be seen that this scheme significantly improves the efficiency of the system.

Another object of the present invention is to provide an LED driving circuit, which includes a rectifier bridge and the above-mentioned LED driving chip.

Another object of the present invention is to provide an LED lamp, which includes a casing and the above-mentioned LED driving circuit.

In this embodiment, since the above-mentioned LED driving circuit includes the above-mentioned LED driving chip, and the voltage adjustment module in the above-mentioned LED driving chip is to supply power to the load by adjusting the voltage of the input terminal of the first switch tube, it is relatively direct The method of adjusting the voltage output by the rectifier bridge has higher efficiency. Applying the LED drive circuit to LED lamps significantly improves the working efficiency of the LED lamps.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (10)

1. An LED driver chip connected to a rectifier bridge and a first LED lamp group, said LED driver chip comprising a switch control module, a first switch tube and a load; said rectifier bridge is connected to an alternating current, and said alternating current is rectified After processing, output to the switch control module and the first LED lamp group, the input end of the first switch tube is connected to the output end of the first LED lamp group, and the switch control module controls the first switch The switching frequency of the tube is used to adjust the current flowing through the first LED lamp group; it is characterized in that: The LED driver chip also includes a first voltage adjustment module; The power supply terminal and the output terminal of the first voltage adjustment module are respectively connected to the input terminal of the first switch tube and the power supply terminal of the load; The first voltage adjustment module connects the output end of the first LED lamp group to direct current, performs voltage conversion processing on the direct current, and supplies power to the load. 2. The LED driver chip according to claim 1, wherein the LED driver chip is also connected to one or more second LED lamp groups, and the LED driver chip also includes one or more second switch tubes , the switch control module also has one or more second control terminals; The number of the one or more second LED lamp groups, the number of the one or more second switch tubes and the number of the one or more second control terminals are equal; The one or more second LED lamp groups start from the output end of the first LED lamp group, and are sequentially connected in series by connecting the input end to the output end; The controlled end of each of the one or more second switch transistors is connected to each of the one or more second control ends in a one-to-one correspondence; The input end of each second switching tube is connected to the output end of each second LED light group in the one or more second LED light groups in one-to-one correspondence; The output terminals of each of the second switching transistors are commonly connected to the ground terminal of the switch control module. 3. The LED driver chip according to claim 2, wherein the LED driver chip further comprises one or more second voltage adjustment modules; The number of the one or more second voltage adjustment modules is equal to the number of the one or more second switch tubes; The power supply terminal of each second voltage adjustment module in the one or more second voltage adjustment modules is connected to the input end of each second switch tube in a one-to-one correspondence, and each of the second voltage adjustment modules The output terminal is connected to the power supply terminal of the load. 4. The LED driver chip according to claim 1, further comprising a first current diversion module connected in series between the first voltage adjustment module and the load; The input terminal and the output terminal of the first current diversion module are respectively connected to the output terminal of the first voltage adjustment module and the power supply terminal of the load. 5. The LED driver chip according to claim 3, further comprising one or more second drainage modules; The number of the one or more second current diversion modules is equal to the number of the one or more second voltage adjustment modules; Each of the one or more second current diversion modules is serially connected between each second voltage adjustment module and the load in a one-to-one correspondence; The input terminals of each second current diversion module are connected to the output terminals of each second voltage adjustment module in one-to-one correspondence, and the output terminals of each second current diversion module are commonly connected to the power supply terminal of the load. 6. The LED driver chip according to claim 1, wherein the enabling terminal of the first voltage adjustment module is connected to the first enabling signal output terminal of the switch control module. 7. The LED driver chip according to claim 6, wherein the first voltage adjustment module comprises: N-type JFET tube, first NMOS tube, second NMOS tube, third NMOS tube, first resistor, second resistor, third resistor, capacitor and voltage regulator tube; The drain of the N-type JFET is the input terminal of the first voltage adjustment module, and the first end of the first resistor and the first end of the second resistor are commonly connected to the N-type JFET. Source, the gate of the first NMOS transistor is the enabling terminal of the first voltage adjustment module, the drain of the first NMOS transistor, the gate of the second NMOS transistor, the second NMOS The drain of the transistor, the second end of the first resistor and the first end of the capacitor are connected to the controlled end of the third NMOS transistor, and the second end of the second resistor is connected to the third The drain of the NMOS transistor, the source of the second NMOS transistor is connected to the first end of the third resistor, the second end of the third resistor is connected to the cathode of the Zener transistor, and the third NMOS transistor The source of the first voltage adjustment module is the output end of the first voltage adjustment module, the gate of the N-type JFET, the source of the first NMOS transistor, the substrate of the first NMOS transistor, the second NMOS transistor The substrate of the transistor, the substrate of the third NMOS transistor and the anode of the Zener transistor are commonly grounded. 8. The LED driver chip according to claim 3, wherein the switch control module also has one or more second enable signal output terminals; The number of the one or more second enable signal output terminals is equal to the number of the one or more second voltage adjustment modules; The enable terminal of each second voltage adjustment module is connected to each second enable signal output terminal of the one or more second enable signal output terminals in a one-to-one correspondence. 9. An LED driving circuit, comprising a rectifier bridge, characterized in that the LED driving circuit further comprises the LED driving chip according to any one of claims 1 to 8. 10. An LED lamp, comprising a housing, and further comprising the LED driving circuit according to claim 9.