WO2019184668A1

WO2019184668A1 - Led driving device, delayed compensation driving circuit, and driving method

Info

Publication number: WO2019184668A1
Application number: PCT/CN2019/077149
Authority: WO
Inventors: 刘梦; 麦炎全; 陈博
Original assignee: 深圳市晟碟半导体有限公司
Priority date: 2018-03-27
Filing date: 2019-03-06
Publication date: 2019-10-03
Also published as: CN108282934A

Abstract

Disclosed are an LED driving device, a delayed compensation driving circuit, and a driving method. The delayed compensation driving circuit comprises a rectification module, a sampling module, a benchmark voltage module, a delayed compensation module, and a constant current source module. A line voltage is sampled by the sampling module, and a sampled current is output according to a sampled voltage. The delayed compensation module outputs, according to the sampled current, a continuously varying compensation current after a delay of a preset time period. A benchmark voltage output by the benchmark voltage module is modulated according to the compensation current, and then a reference voltage is output to the constant current source module. The constant current source module is controlled to perform constant current driving on an LED light string. The invention adopts a delayed compensation technique, such that output of a sampled current occurs before a constantly varying compensation current is output following a delay of a preset time period. The delay slows changing of a current, thereby preventing a sudden change in the current, effectively suppressing self-excitation of a power supply, and improving the stability of a driving power supply.

Description

LED driving device and delay compensation driving circuit and driving method

Technical field

The invention relates to the technical field of LEDs, in particular to an LED driving device, a delay compensation driving circuit and a driving method.

Background technique

As shown in Figure 1, it is a common line voltage compensation drive circuit frame diagram. By adding a compensation circuit to prevent the line voltage VAC from being too high, the input power is too high. The sampling power is used to sample the power supply VAC voltage and output it to the compensation circuit. The compensation circuit changes the reference voltage output to the constant current source, thereby changing the source voltage VCS of the constant current source power tube. 2 is a simulation waveform diagram of the common line voltage compensation driving circuit of FIG. 1, wherein VAC is the output voltage of the rectifier bridge, VD is the voltage under the LED string, IS is the current flowing through the sampling circuit, and IC is the compensation branch flowing through. Current, VIP is the reference voltage generated by the reference circuit, VCS is the voltage on the sampling resistor RCS, and the source voltage of the constant current source power tube.

As shown in Figure 2, due to the common line voltage compensation circuit, usually the compensation circuit and the sampling circuit are in a synchronous relationship. When VAC rises (before point A), the voltage on VD is small, and the sampling circuit current IS is zero. The circuit current IC is also zero, VCS gradually rises, when the voltage of VD is high enough (A), the sampling circuit current IS can not be ignored, the compensation circuit reflects the sampling circuit current in real time, this current can not be ignored, so at A, due to compensation The appearance of current IC, VCS mutation at this moment, causing a sudden change in the current of the power supply VAC, due to the parasitic inductance in the circuit

VAC will be self-excited at A, causing the LED drive power to be unstable, affecting the LED load to work properly.

Therefore, the prior art has yet to be improved and improved.

Summary of the invention

In view of the above-mentioned deficiencies of the prior art, an object of the present invention is to provide an LED driving device, a delay compensation driving circuit and a driving method, which are delayed by a delay time after outputting a sampling current and then output continuously. The varying compensation current and the delay effect make the current change slow without sudden change of current, effectively suppressing the self-excitation of the power supply and improving the stability and safety of the LED drive.

In order to achieve the above object, the present invention adopts the following technical solutions:

A delay compensation driving circuit comprises a rectifying module for rectifying an input alternating current and outputting a line voltage to an LED string, and further comprising a sampling module, a reference voltage module, a delay compensation module and a constant current source module; and the sampling module Sampling the line voltage and outputting the sampling current according to the sampling voltage, the delay compensation module outputs a continuously varying compensation current after the preset time according to the sampling current, and according to the reference of the compensation current to the reference voltage module output After the voltage is modulated, the reference voltage is output to the constant current source module, and the constant current source module is controlled to perform constant current driving on the LED light string.

In the delay compensation driving circuit, the delay compensation module is specifically configured to output a compensation current that continuously changes and the absolute value of the slope is less than a preset threshold after the preset time is delayed according to the sampling current.

In the delay compensation driving circuit, an input end of the rectifier module inputs an alternating current, an output end of the rectifier module is connected to a positive pole of the LED light string, and an input end of the sampling module is connected to an output end of the rectifier module or Connecting a negative pole of the LED light string, the negative pole of the LED light string is further connected to the constant current source module, and an output end of the sampling module is connected to the first end of the delay compensation module, and the delay compensation module is The second end is connected to the reference voltage module, and the third end of the delay module is connected to the control end of the constant current source module.

In the delay compensation driving circuit, the sampling module includes a first resistor and a first MOS transistor; one end of the first resistor is an input end of the sampling module, and is connected to an output end of the rectifier module or connected a cathode of the LED string, the other end of the first resistor is connected to the drain of the first MOS transistor; the gate of the first MOS transistor is an output end of the sampling module, and the drain of the first MOS transistor is connected At the first end of the delay compensation module, the source of the first MOS transistor is grounded.

In the delay compensation driving circuit, the delay compensation module includes a second resistor, a third resistor, a fourth resistor, a capacitor, and a second MOS transistor; one end of the second resistor is the delay compensation module The first end of the sampling module is connected to the output end of the sampling module, the other end of the second resistor is connected to one end of the capacitor and the gate of the second MOS tube; the drain of the second MOS tube is the delay compensation module The third end of the constant current source module is connected to one end of the third current resistor and one end of the fourth resistor; the other end of the third resistor is the second end of the delay compensation module, The reference voltage module; the other end of the capacitor, the source of the second MOS transistor, and the other end of the fourth resistor are grounded.

In the delay compensation driving circuit, the delay compensation module includes a third resistor, a fourth resistor, a capacitor, and a second MOS transistor; the source of the second MOS transistor is the first of the delay compensation module a terminal connected to the output end of the sampling module, a drain of the second MOS transistor being a third end of the delay compensation module, connecting one end of the capacitor, one end of the third resistor, one end of the fourth resistor, and a control end of the constant current source module; the other end of the third resistor is a second end of the delay compensation module, connected to the reference voltage module; the other end of the capacitor, the source of the second MOS tube The other ends of the pole and the fourth resistor are both grounded.

In the delay compensation driving circuit, the constant current source module includes an operational amplifier, a third MOS transistor and a fifth resistor; a non-inverting input terminal of the operational amplifier is a control end of the constant current source module, and a connection end The third end of the delay compensation module, the inverting input end of the operational amplifier is connected to the source of the third MOS transistor and one end of the four or five resistors, and the output end of the operational amplifier is connected to the gate of the third MOS transistor; The drain of the third MOS transistor is connected to the cathode of the LED string; the other end of the fifth resistor is grounded.

A delay compensation driving method includes the following steps:

The line voltage is sampled by the sampling module, and the sampling current is output according to the sampling voltage;

The delay compensation module outputs a continuously varying compensation current after the preset time according to the sampling current, and modulates the reference voltage output by the reference voltage module according to the compensation current, and then outputs the reference voltage to the constant current source module;

The constant current source module performs constant current driving on the LED light string.

In the delay compensation driving method, the step of the delay compensation module outputting the continuously varying compensation current after the preset time is delayed according to the sampling current includes:

The delay compensation module outputs a compensation current that continuously changes and the absolute value of the slope is less than a preset threshold after the preset time is delayed according to the sampling current.

An LED driving device includes a casing in which a PCB board is disposed, and the PCB board is provided with a delay compensation driving circuit as described above.

Compared with the prior art, in the LED driving device, the delay compensation driving circuit and the driving method provided by the present invention, the delay compensation driving circuit includes a rectification for outputting the line voltage to the LED string after rectifying the input alternating current. The module further includes a sampling module, a reference voltage module, a delay compensation module and a constant current source module; the sampling voltage is used to sample the line voltage, and the sampling current is output according to the sampling voltage, and the delay compensation module delays according to the sampling current. Outputting a continuously varying compensation current after a preset time, and modulating the reference voltage output by the reference voltage module according to the compensation current, and outputting a reference voltage to the constant current source module, and controlling the constant current source module to the LED light string Constant current drive. The delay compensation method is used to delay the preset time after outputting the sampling current and then output the continuously varying compensation current. The delay action makes the current change slow without sudden change of current, effectively suppressing the self-excitation of the power supply and improving the stability of the LED drive. Sex and safety.

DRAWINGS

1 is a structural block diagram of a line voltage compensation driving circuit in the prior art.

2 is a simulation waveform diagram of each circuit node of the existing line voltage compensation driving circuit as a function of VAC voltage.

FIG. 3 is a structural block diagram of a first preferred embodiment of a delay compensation driving circuit according to the present invention.

4 is a structural block diagram of a second preferred embodiment of a delay compensation driving circuit according to the present invention.

FIG. 5 is a circuit diagram of a first embodiment of a delay compensation driving circuit according to the present invention.

FIG. 6 is a circuit diagram of a second embodiment of a delay compensation driving circuit according to the present invention.

FIG. 7 is a simulation waveform diagram of each circuit node in a delay compensation driving circuit according to the present invention as a function of VAC voltage.

FIG. 8 is a flowchart of a delay compensation driving method provided by the present invention.

detailed description

In view of the shortcomings of the prior art, the line voltage compensation circuit may cause self-excitation of the power source, and the like, the object of the present invention is to provide an LED driving device, a delay compensation driving circuit and a driving method, and delaying the output of the sampling current by the delay compensation method. The preset time then outputs the continuously varying compensation current, and the delay action makes the current change slow without sudden change of current, which effectively suppresses the self-excitation phenomenon of the power supply and improves the stability and safety of the LED drive.

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.

Please refer to FIG. 3 and FIG. 4 , which are two preferred embodiments of the present invention. The delay compensation driving circuit provided by the present invention is connected to the LED light string 10 , and includes a rectifier module 11 , a sampling module 12 , and a reference voltage module 13 . The delay compensation module 14 and the constant current source module 15 , wherein the input end of the rectifier module 11 inputs an alternating current, and the output end of the rectifier module 11 is connected to the anode of the LED string 10 , wherein in the first preferred embodiment, The input end of the sampling module 12 is connected to the output end of the rectifier module 11. In the second preferred embodiment, the input end of the sampling module 12 is connected to the negative pole of the LED string 10, that is, the sampling module 12 can be from the LED lamp. The sampling of the line voltage is performed on the front end or the back end of the string 10, and the sampling output is achieved. In the two preferred embodiments, the negative pole of the LED string 10 is also connected to the constant current source module 15, the sampling module. The output end of the delay compensation module 14 is connected to the first end of the delay compensation module 14, the second end of the delay compensation module 14 is connected to the reference voltage module 13, and the third end of the delay module is connected to the constant current The control terminal of the source module 15, the rectifier module 11 is a whole Flow bridge.

In the first preferred embodiment, the input AC power is rectified by the rectifying module 11 to output the line voltage to the LED string 10, and the line voltage is directly sampled by the sampling module 12, and the sampling current is output according to the sampling voltage, and the second comparison is performed. In a preferred embodiment, the input AC power is rectified by the rectifier module 11 to output the line voltage to the LED string 10, and the line voltage after being stepped down by the LED string 10 is sampled by the sampling module 12, and the sampling current is output according to the sampling voltage. That is, the voltage sampled in the second preferred embodiment is the voltage after the line voltage has passed a certain number of LED voltage drops, and also includes the characteristics of the line voltage. Therefore, the two preferred embodiments can realize the sampling of the line voltage, In a preferred embodiment, after the sampling current is acquired, the delay compensation module 14 outputs a continuously varying compensation current after the preset time according to the sampling current, and outputs the compensation current to the reference voltage module 13 according to the compensation current. After the reference voltage is modulated, the reference voltage is output to the constant current source module 15, and the constant current source module 15 is controlled to perform constant current driving on the LED string 10 due to the delay. The compensation module 14 and the sampling module 12 do not synchronize the output current, and the compensation current and the sampling current are separated by a preset time, and the two are in a delay relationship. Therefore, under the action of the delay, the current change at the compensation starting point is slow, and will not A sudden change in current is generated, which effectively suppresses self-excitation of the power supply.

The invention rectifies the output line voltage VAC to the LED string 10 through the rectifying module 11, and then directly samples the line voltage VAC through the sampling module 12, or samples the line voltage VAC stepped down by the LED string 10, that is, the LED The voltage is sampled below the string 10 to obtain the sampling voltage VD, and the sampling current is output to the delay compensation module 14 according to the sampling voltage VD. At this time, the delay compensation template does not output the corresponding compensation current in real time, but delays the preset time. Output, due to the delay action, the compensation current will increase slowly from zero continuously. Because the current changes slowly, the reference voltage output after the modulation of the reference voltage is also changed slowly, so that the sampling resistor in the constant current source module 15 The voltage drop speed is also slow, and the power supply self-excitation phenomenon caused by the sudden change of the voltage on the sampling resistor is not generated, thereby effectively improving the stability and reliability of the LED driving power source.

Preferably, the delay compensation module 14 is configured to output a compensation current that continuously changes and the absolute value of the slope is less than a preset threshold after the preset time is delayed according to the sampling current, and generates a compensation current synchronously with the prior art. The difference between the current and voltage of each node in the compensation starting point circuit is different. In this embodiment, the delay compensation module 14 outputs a continuous change after the preset time of the sampling current output, and the absolute value of the slope is smaller than the preset. The compensation current of the threshold is specifically implemented. The delay compensation module 14 includes an RC delay circuit. Under the action of the RC delay circuit, a continuous slowly varying compensation current is output, and the rising or falling speed of the compensation current is compensated. The slope of the current curve, the absolute value of the slope is less than the preset threshold, that is, the maximum rising or falling speed will be less than the speed corresponding to the preset threshold, and the preset threshold is the maximum slope corresponding to the sampling current curve, ensuring the output to the constant current The reference voltage controlled by the source module 15 does not cause a sudden change, thereby ensuring that the voltage on the sampling resistor in the constant current source module 15 does not abruptly change. Since the effect of suppressing the excited.

Further, in the following specific embodiments, the specific circuit of the delay compensation driving circuit and the working process thereof are described in detail in the second preferred embodiment. Referring to FIG. 5 and FIG. 6, which is a second preferred embodiment of the present invention. The two specific application embodiments provided by the embodiment, the sampling module 12 includes a first resistor R1 and a first MOS transistor M1; one end of the first resistor R1 is an input end of the sampling module 12, and the LED string is connected The other end of the first resistor R1 is connected to the drain of the first MOS transistor M1; the gate of the first MOS transistor M1 is the output end of the sampling module 12, and is connected to the drain of the first MOS transistor M1. And a first end of the delay compensation module 14, the source of the first MOS transistor M1 is grounded. The VD voltage of the negative pole of the LED string 10 is sampled by a sampling circuit composed of the first resistor R1 and the first MOS transistor M1 and the sampling current IS is output for the supplementary current output of the subsequent delay compensation circuit.

Specifically, in the first embodiment provided by the present invention, as shown in FIG. 5, the delay compensation module 14 includes a second resistor R2, a third resistor R3, a fourth resistor R4, a capacitor C1, and a second MOS transistor M2. One end of the second resistor R2 is the first end of the delay compensation module 14, and is connected to the output end of the sampling module 12. The other end of the second resistor R2 is connected to one end of the capacitor C1 and the second MOS. The drain of the second MOS transistor M2 is the third end of the delay compensation module 14, and is connected to the control end of the constant current source module 15, the end of the third resistor R3, and the fourth resistor. The other end of the third resistor R3 is the second end of the delay compensation module 14, and is connected to the reference voltage module 13; the other end of the capacitor C1 and the source of the second MOS transistor M2 The other end of the fourth resistor R4 is grounded.

In this embodiment, the second resistor R2 and the capacitor C1 in the delay supplement module constitute an RC delay circuit, and the compensation current IC is a current flowing through the drain of the second MOS transistor M2, because the second MOS transistor M2 and the first MOS There is an RC delay between the gates of the tube M1, so the gate voltage of the second MOS transistor M2 is later than the gate voltage of the first MOS transistor M1, so that the compensation current IC generated by the second MOS transistor M2 is later than the first The sampling current IS of a MOS transistor M1, in turn, achieves the effect of the delayed output. In this embodiment, the range of the preset delay time can be set by adjusting the resistance and capacitance of the second resistor R2 and the capacitor C1. The range is preferably 100us-500us, which can be adjusted according to actual needs.

In the second embodiment provided by the present invention, as shown in FIG. 6, the delay compensation module 14 includes a third resistor R3, a fourth resistor R4, a capacitor C1, and a second MOS transistor M2; the second MOS transistor M2 The first end of the delay compensation module 14 is connected to the output end of the sampling module 12, and the drain of the second MOS transistor M2 is the third end of the delay compensation module 14, and the connection is One end of the capacitor C1, one end of the third resistor R3, one end of the fourth resistor R4, and the control end of the constant current source module 15; the other end of the third resistor R3 is the second of the delay compensation module 14 And connecting the reference voltage module 13; the other end of the capacitor C1, the source of the second MOS transistor M2, and the other end of the fourth resistor R4 are grounded.

In this embodiment, the fourth resistor R4 and the capacitor C1 in the delay supplement module constitute an RC delay circuit, and the compensation current IC is a current flowing through the drain of the second MOS transistor M2 and the capacitor C1 due to flowing through the second MOS transistor. The current of M2 completely mirrors the sampling current IS of the first MOS transistor M1, and the compensation current IC also contains the current of the capacitor C1. Under the delay of the capacitor C1 and the fourth resistor R4, the compensation current IC is also later than the first The sampling current IS of a MOS transistor M1, in turn, achieves the effect of the delayed output. In this embodiment, the range of the delay preset time can be set by adjusting the resistance and capacitance of the fourth resistor R4 and the capacitor C1. The range is preferably 100us-500us, which can be adjusted according to actual needs.

Further, in the two embodiments provided by the present invention, after the sampling current is obtained, the reference voltage outputted by the reference voltage module 13 is modulated by the third resistor R3 and the fourth resistor R4, and then the reference voltage VIP is outputted to the constant current source. The control terminal of the module 15 controls the constant current source module 15 to perform constant current driving on the LED light string 10 to realize a delayed and continuously changing line voltage compensation driving, and the reference voltage may be directly provided by a constant voltage source. Or partial pressure is provided.

Further, the constant current source module 15 includes an operational amplifier A1, a third MOS transistor M3, and a fifth resistor R5. The non-inverting input terminal of the operational amplifier A1 is a control end of the constant current source module 15, and is connected to the The third end of the delay compensation module 14, the inverting input terminal of the operational amplifier A1 is connected to the source of the third MOS transistor M3 and one end of the four-five resistor, and the output terminal of the operational amplifier A1 is connected to the third MOS transistor M3. The drain of the third MOS transistor M3 is connected to the cathode of the LED string 10; the other end of the fifth resistor R5 is grounded. The fifth resistor R5 is a sampling resistor in the constant voltage source module, and the operational amplifier A1 amplifies the voltage difference between the compensation voltage VIP and the voltage VCS collected by the sampling resistor to drive the third MOS transistor M3 to realize constant current driving.

The first MOS transistor M1, the second MOS transistor M2, and the third MOS transistor M3 are all NMOS transistors.

To better understand the driving process and effect of the delay compensation driving circuit provided by the present invention, the working principle of the delay compensation driving circuit provided by the present invention will be explained in the following with reference to FIG. 5 and FIG.

The rectifier bridge rectifies the input alternating current and outputs the line voltage VAC to the LED string 10, and the line voltage VAC is stepped down by the LED string 10, and the LED string 10 is sampled by a sampling circuit composed of the first resistor R1 and the first MOS tube M1. The VD voltage of the negative electrode outputs the sampling current IS. Since there is an RC delay between the second MOS transistor M2 and the gate of the first MOS transistor M1, the gate voltage of the second MOS transistor M2 is later than the first MOS transistor M1. The gate voltage is such that the compensation current IC generated by the second MOS transistor M2 is later than the sampling current IS of the first MOS transistor M1, and the modulated reference voltage IS is output according to the sampling current IS of the delayed output to the in-phase of the operational amplifier A1. At the input end, the operational amplifier A1 amplifies the voltage difference between the compensation voltage VIP and the voltage VCS collected by the sampling resistor to drive the third MOS transistor M3 to realize the delay compensation constant current driving.

In this process, please refer to the voltage and current simulation waveforms provided in Figure 7. When the VAC voltage rises to a preset voltage (ie, point A in FIG. 7), the voltage at the negative pole of the LED string 10, that is, the VD voltage is small, and the sampling current IS is negligible at this time, and the compensation obtained after the delay is obtained. The current IC is also zero, and the VCS voltage gradually rises;

When the VAC voltage rises to a preset voltage, the sampling current IS is not negligible, but due to the delay of the RC delay circuit, the compensation current IC at this time is still zero;

When the VAC voltage continues to rise, the sampling current IS also gradually increases. Due to the delay, the compensation current IC will slowly increase from zero after the preset time (as shown by the dotted line of the IC current in Figure 7). The starting point, that is, the delay time can be changed by adjusting the parameters of the RC delay circuit, and the current is slower than the current change. At this time, the falling speed of the reference voltage VIP is slowed down (as indicated by the dotted line of the VIP voltage in Fig. 7), and the VCS voltage is decreased. The speed is also slow (as shown by the dotted line of the VCS voltage in Figure 7), and there is no sudden change of voltage and current. Therefore, the parasitic inductance in the circuit does not cause the power supply to generate self-excitation at A, effectively achieving self-excitation suppression of the power supply. Improve the stability of the LED driver power supply.

Correspondingly, the present invention further provides a delay compensation driving method. As shown in FIG. 8, the delay compensation driving method includes the following steps:

S100, sampling, by the sampling module, the line voltage after being stepped down by the LED light string, and outputting the sampling current according to the sampling voltage;

S200. The delay compensation module outputs a continuously varying compensation current after the preset time according to the sampling current, and modulates the reference voltage output by the reference voltage module according to the compensation current, and outputs the reference voltage to the constant current source module. ;

S300. The constant current source module performs constant current driving on the LED light string.

The step S200 specifically includes: the delay compensation module outputs a compensation current that continuously changes and the absolute value of the slope is less than a preset threshold after the preset time is delayed according to the sampling current. For details, please refer to the corresponding embodiment of the above product.

The invention further provides an LED driving device, comprising a casing, wherein the casing is provided with a PCB board, and the PCB board is provided with a delay compensation driving circuit as described above, since the delay compensation has been described above The driver circuit is described in detail and will not be described in detail here.

In summary, in the LED driving device, the delay compensation driving circuit and the driving method provided by the present invention, the delay compensation driving circuit is connected with the LED light string, and comprises an output line voltage to the LED after rectifying the input alternating current. The rectifier module of the light string further comprises a sampling module, a reference voltage module, a delay compensation module and a constant current source module; the sampling voltage is used to sample the line voltage, and the sampling current is output according to the sampling voltage, and the delay compensation module is based on the sampling The current outputs a continuously varying compensation current after delaying the preset time, and modulates the reference voltage output by the reference voltage module according to the compensation current, and then outputs a reference voltage to the constant current source module to control the constant current source module The LED light string is driven by a constant current. The delay compensation method is used to delay the preset time after outputting the sampling current and then output the continuously varying compensation current. The delay action makes the current change slow without sudden change of current, effectively suppressing the self-excitation of the power supply and improving the stability of the LED drive. Sex and safety.

It is to be understood that those skilled in the art can make equivalent substitutions or changes to the inventions and the inventions of the present invention, and all such changes or substitutions fall within the scope of the appended claims.

Claims

A delay compensation driving circuit comprises: a rectifying module for rectifying an input alternating current and outputting a line voltage to an LED light string, wherein the sampling module, the reference voltage module, the delay compensation module and the constant current source module are further included The sampling voltage is used to sample the line voltage, and the sampling current is output according to the sampling voltage. The delay compensation module outputs a continuously varying compensation current after the preset time according to the sampling current, and the reference voltage is determined according to the compensation current. The reference voltage outputted by the module is modulated to output a reference voltage to the constant current source module, and the constant current source module is controlled to perform constant current driving on the LED light string.
The delay compensation driving circuit of claim 1 , wherein the delay compensation module is configured to output a continuous change after the preset time is delayed according to the sampling current, and an absolute value of the slope is less than a preset. The compensation current of the threshold.
The delay compensation driving circuit of claim 1 , wherein an input end of the rectifier module inputs an alternating current, an output end of the rectifier module is connected to a positive pole of the LED light string, and an input end of the sampling module is connected The output end of the rectifier module is connected to the negative pole of the LED string, the cathode of the LED string is also connected to the constant current source module, and the output end of the sampling module is connected to the first end of the delay compensation module. The second end of the delay compensation module is connected to the reference voltage module, and the third end of the delay module is connected to the control end of the constant current source module.
The delay compensation driving circuit according to claim 3, wherein the sampling module comprises a first resistor and a first MOS transistor; one end of the first resistor is an input end of the sampling module, and the connection is The output end of the rectifier module is connected to the negative pole of the LED string, the other end of the first resistor is connected to the drain of the first MOS tube; the gate of the first MOS tube is the output end of the sampling module, and the connection is first. The drain of the MOS transistor and the first end of the delay compensation module, the source of the first MOS transistor is grounded.
The delay compensation driving circuit according to claim 3, wherein the delay compensation module comprises a second resistor, a third resistor, a fourth resistor, a capacitor and a second MOS transistor; and one end of the second resistor The first end of the delay compensation module is connected to the output end of the sampling module, and the other end of the second resistor is connected to one end of the capacitor and the gate of the second MOS tube; the drain of the second MOS tube The third end of the delay compensation module is connected to the control end of the constant current source module, one end of the third resistor, and one end of the fourth resistor; the other end of the third resistor is the delay compensation module. The second end of the capacitor is connected to the reference voltage module; the other end of the capacitor, the source of the second MOS transistor, and the other end of the fourth resistor are grounded.
The delay compensation driving circuit according to claim 3, wherein the delay compensation module comprises a third resistor, a fourth resistor, a capacitor and a second MOS transistor; the source of the second MOS transistor is substantially The first end of the delay compensation module is connected to the output end of the sampling module, and the drain of the second MOS tube is the third end of the delay compensation module, and one end of the capacitor and one end of the third resistor are connected One end of the fourth resistor and the control end of the constant current source module; the other end of the third resistor is the second end of the delay compensation module, and the reference voltage module is connected; the other end of the capacitor The source of the second MOS transistor and the other end of the fourth resistor are both grounded.
The delay compensation driving circuit according to claim 3, wherein the constant current source module comprises an operational amplifier, a third MOS transistor and a fifth resistor; and the non-inverting input terminal of the operational amplifier is the constant current source a control terminal of the module is connected to the third end of the compensation module, an inverting input end of the operational amplifier is connected to a source of the third MOS transistor and one end of the four-five resistor, and an output end of the operational amplifier is connected to the third MOS a gate of the tube; a drain of the third MOS transistor is connected to a cathode of the LED string; and the other end of the fifth resistor is grounded.
A delay compensation driving method, comprising the following steps:

The line voltage is sampled by the sampling module, and the sampling current is output according to the sampling voltage;

The delay compensation module outputs a continuously varying compensation current after the preset time according to the sampling current, and modulates the reference voltage output by the reference voltage module according to the compensation current, and then outputs the reference voltage to the constant current source module;

The constant current source module performs constant current driving on the LED light string.
The delay compensation driving method according to claim 8, wherein the step of the delay compensation module outputting the continuously varying compensation current after the preset time is delayed according to the sampling current comprises:

The delay compensation module outputs a compensation current that continuously changes and the absolute value of the slope is less than a preset threshold after the preset time is delayed according to the sampling current.
An LED driving device includes a casing, and a PCB board is disposed in the casing, wherein the PCB board is provided with a delay compensation driving circuit according to any one of claims 1-7.