Driving control circuit, driving control method thereof and LED driver

Abstract

The invention provides a driving control circuit, a driving control method thereof and an LED driver. The drive control circuit comprises a detection circuit, a compensation voltage generation circuit and a drive circuit. The input end of the detection circuit is used for being coupled with the switch tube to obtain a detection signal, the detection circuit is used for generating a trigger signal according to the detection signal representing the drain voltage of the switch tube, and when the detection signal is larger than a preset voltage for a preset time, the trigger signal is controlled to be at a first level. When the detection signal is smaller than the reference voltage, the trigger signal is controlled to be at a second level. The input end of the compensation voltage generation circuit is coupled with the detection circuit, and the compensation voltage generation circuit is used for generating compensation voltage according to the trigger signal. The driving circuit is used for generating driving signals according to the compensation voltage. According to the drive control circuit, the drive control method thereof and the LED driver provided by the invention, the problem of stroboflash when the LED driver is started or the preceding-stage current is suddenly increased is effectively solved, and the capacitance value of the output capacitor does not need to be increased.

Description

Technical Field

[0001] The invention belongs to the field of power electronics, and relates to an LED driving technology, and in particular to a driving control circuit and a driving control method thereof, and an LED driver. Background Art

[0002] LED lamps are widely used in the lighting field due to their advantages of energy saving, environmental protection, good color rendering, etc. In specific circuit applications, LED drivers provide stable current to LED lamps to drive them to work normally.

[0003] However, most LED products on the market have severe flicker when they are turned on. Flicker can have adverse effects on human health, so a flicker-free circuit design is required. Figure 1 As shown in the figure, the implementation principle is to filter the drain voltage Vdrain and convert it into a stable compensation voltage Vcom, and then pass it through the constant current loop amplifier circuit AMP to achieve low ripple of the load current ILED. In order to further reduce the ripple in the load current ILED, the bandwidth of the compensation voltage regulation circuit is very slow, which will lead to the problem of poor dynamic performance of the LED driver's ripple removal system. Figure 2 It can be seen that when the LED driver is started, the energy of the previous stage changes very quickly, and the drain voltage Vdrain rises very quickly, causing the compensation voltage Vcom to rise too much, and I LED*Rcs follows Vcom, so a large overcharge occurs on the load current I LED, causing the light to flicker. The prior art proposes a solution, which reduces the ripple of the drain voltage Vdrain by increasing the capacitance value of the output capacitor Cout, thereby improving the bandwidth of the compensation voltage regulation link of the LED driver, but this method will increase the volume and circuit size, which is not conducive to the miniaturization of circuit devices.

[0004] In view of this, it is necessary to provide a new structure or control method to solve at least part of the above problems. Summary of the invention

[0005] In view of one or more problems in the prior art, the present invention proposes a drive control circuit and a drive control method thereof and an LED driver.

[0006] According to one aspect of the present invention, a drive control circuit is disclosed. The drive control circuit is used to control a switch tube in an LED driver. The drive control circuit includes:

[0007] A detection circuit, whose input end is used to couple the switch tube to obtain a detection signal, and is used to generate a trigger signal according to the detection signal representing the drain voltage of the switch tube, and when the detection signal is greater than a preset voltage for a preset time, the trigger signal is controlled to be at a first level, and when the detection signal is less than a reference voltage, the trigger signal is controlled to be at a second level, and the preset voltage is greater than or equal to the reference voltage;

[0008] a compensation voltage generating circuit, whose input terminal is coupled to the output terminal of the detection circuit, for generating a compensation voltage according to a trigger signal; when the trigger signal is at a first level, controlling the compensation voltage to increase in a stepwise manner and change with a preset amplitude, and when the trigger signal changes from the first level to a second level, reducing the amplitude of the compensation voltage change; and

[0009] The driving circuit has an input end coupled to the compensation voltage generating circuit and is used to generate a driving signal according to the compensation voltage to control the switch tube.

[0010] In one embodiment, the detection circuit comprises:

[0011] A comparison circuit, wherein a first input terminal is coupled to the drain of the switch tube, a second input terminal is coupled to the preset voltage terminal to receive a preset voltage, and an output terminal outputs a comparison signal; and

[0012] The dynamic detection circuit has an input terminal coupled to the output terminal of the comparison circuit and is used to generate a trigger signal according to the comparison signal.

[0013] In one embodiment, the compensation voltage generating circuit includes:

[0014] A compensation voltage regulating circuit, whose input end is used to couple to the drain of the switch tube, and whose output end is used to couple to the first end of the compensation capacitor; and

[0015] a variable resistor, a first end of which is used to couple to the second end of the compensation capacitor, and a second end of which is coupled to the ground; and

[0016] The resistance control circuit has a first input terminal coupled to the output terminal of the detection circuit and is used to control the resistance value of the variable resistor according to the trigger signal.

[0017] In one embodiment, the second input terminal of the resistance control circuit is coupled to the first terminal of the variable resistor, and the resistance control circuit is used to adjust the resistance value of the variable resistor according to the voltage of the first terminal of the variable resistor after the trigger signal changes from the first level to the second level.

[0018] In one embodiment, the resistance control circuit is used to gradually reduce the resistance value of the variable resistor after the trigger signal changes from the first level to the second level.

[0019] In one embodiment, the compensation voltage generating circuit includes:

[0020] The digital compensation circuit has a first input terminal coupled to the drain of the switch tube and a second input terminal coupled to the output terminal of the detection circuit, and is used to filter the detection signal to obtain a processing signal, and generate a compensation voltage according to the processing signal and the trigger signal.

[0021] In one embodiment, after the trigger signal is at the first level, the compensation voltage changes in size in the form of a sine wave, a sawtooth wave, or a step wave.

[0022] According to another aspect of the present invention, an LED driver is disclosed, the LED driver comprising a drive control circuit as described in any one of the above items, the drive control circuit being used to control a switching state of a switch tube.

[0023] According to another aspect of the present invention, a drive control method is disclosed. The drive control method is used to control a drive control circuit. The drive control method includes:

[0024] Generate a trigger signal according to a detection signal representing the drain voltage of the switch tube, control the trigger signal to be at a first level when the detection signal is greater than a preset voltage for a preset time, and control the trigger signal to be at a second level when the detection signal is less than a reference voltage, and the preset voltage is greater than or equal to the reference voltage;

[0025] Generate a compensation voltage according to a trigger signal; when the trigger signal is at a first level, control the compensation voltage to increase in a stepwise manner and change with a preset amplitude, and when the trigger signal changes from the first level to a second level, reduce the amplitude of the compensation voltage change; and

[0026] A driving signal is generated according to the compensation voltage to control the switch tube.

[0027] In one embodiment, the drive control circuit includes a variable resistor, which is used to couple the compensation capacitor. The step of generating the compensation voltage according to the trigger signal also includes: gradually reducing the resistance value of the variable resistor when the trigger signal changes from the first level to the second level.

[0028] In one embodiment, the drive control circuit includes a variable resistor, which is used to couple the compensation capacitor. The step of generating a compensation voltage according to the trigger signal also includes: adjusting the resistance value of the variable resistor according to the voltage at the first end of the variable resistor when the trigger signal changes from the first level to the second level.

[0029] The present invention proposes a driving control circuit and a driving control method thereof and an LED driver. The driving control circuit is used to control a switch tube in an LED driver, and the driving control circuit includes a detection circuit, a compensation voltage generating circuit and a driving circuit. The input end of the detection circuit is used to couple the switch tube to obtain a detection signal, and the detection circuit is used to generate a trigger signal according to the detection signal representing the drain voltage of the switch tube. When the detection signal is greater than a preset voltage and lasts for a preset time, the trigger signal is controlled to be at a first level, and when the detection signal is less than a reference voltage, the trigger signal is controlled to be at a second level. Among them, the preset voltage is greater than or equal to the reference voltage. The input end of the compensation voltage generating circuit is coupled to the output end of the detection circuit, and the compensation voltage generating circuit is used to generate a compensation voltage according to the trigger signal; when the trigger signal is at the first level, the compensation voltage is controlled to increase in a step-wise manner and change with a preset amplitude, and when the trigger signal changes from the first level to the second level, the amplitude of the compensation voltage change is reduced. The input end of the driving circuit is coupled to the compensation voltage generating circuit, and the driving circuit is used to generate a driving signal according to the compensation voltage to control the switch tube. A drive control circuit and a drive control method thereof and an LED driver proposed in the present invention effectively solve the flicker problem during the startup phase of the LED driver or when the front-stage current suddenly increases, and there is no need to increase the capacitance value of the output capacitor, thereby reducing the cost and volume of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and are used together with the description to explain the embodiments of the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 A circuit structure schematic diagram of a conventional LED driver is shown;

[0032] Figure 2 A signal waveform diagram of a LED driver in the prior art is shown;

[0033] Figure 3 A schematic diagram of the circuit structure of a drive control circuit according to an embodiment of the present invention is shown;

[0034] Figure 4 A schematic diagram of the circuit structure of an LED driver according to an embodiment of the present invention is shown;

[0035] Figure 5 FIG. 4 is a schematic diagram showing signal waveforms of an LED driver according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0037] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments. The combination of different embodiments, the mutual replacement of some technical features in different embodiments, and the mutual replacement of the same or similar prior art means with some technical features in the embodiments are also within the scope of the description and protection of the present invention.

[0038] "Coupled" or "connected" in the specification includes both direct connection and indirect connection. Indirect connection is a connection through an intermediate medium, such as a connection through an electrically conductive medium such as a conductor, wherein the electrically conductive medium may contain parasitic inductance or parasitic capacitance, or a connection through an intermediate circuit or component described in the embodiments in the specification; an indirect connection may also include a connection through other active or passive devices on the basis of achieving the same or similar functions, such as a connection through circuits or components such as switches, signal amplification circuits, and follower circuits. "Multiple" or "many" means two or more. In addition, in the present invention, words such as first and second are mainly used to distinguish one technical feature from another technical feature, and do not necessarily require or imply that there is a certain actual relationship or order between these technical features.

[0039] like Figure 3 As shown, an embodiment of the present invention discloses a drive control circuit, which is used to control the switch state of a switch tube in an LED driver. The drive control circuit includes a detection circuit 10, a compensation voltage generating circuit 20 and a drive circuit 30. The input end of the detection circuit 10 is used to couple the switch tube to obtain a detection signal Vdrain, and the detection circuit 10 is used to generate a trigger signal according to the detection signal characterizing the drain voltage of the switch tube. When the detection signal Vdrain is greater than a preset voltage and lasts for a preset time, the detection circuit 10 controls the trigger signal to be at a first level (e.g., a high level). When the detection signal Vdrain is less than a reference voltage, the detection circuit 10 controls the trigger signal to be at a second level (e.g., a low level). Wherein, the preset voltage is greater than or equal to the reference voltage. In one embodiment, the detection signal is the drain voltage of the switch tube. In another embodiment, the detection signal is a divided voltage of the drain voltage of the switch tube. In yet another embodiment, the detection signal is positively correlated with the drain voltage of the switch tube.

[0040] like Figure 3In one embodiment, the input end of the compensation voltage generating circuit 20 is coupled to the output end of the detection circuit 10, and the compensation voltage generating circuit 20 is used to generate the compensation voltage according to the trigger signal. Specifically, when the trigger signal is at a first level (e.g., a high level), the compensation voltage generating circuit 20 controls the compensation voltage to increase in a step-wise manner and change with a preset amplitude. When the trigger signal changes from the first level (e.g., a high level) to the second level (e.g., a low level), the compensation voltage generating circuit 20 reduces the amplitude of the compensation voltage change. The step-wise increase of the compensation voltage can be understood as the rate of change of the increase of the compensation voltage being greater than the preset value. The preset amplitude can be a fixed value or a small amplitude change. After the compensation voltage is increased in a step-wise manner, the compensation voltage changes in size around a value with a preset amplitude. The compensation voltage changes in size in the form of a sine wave, a sawtooth wave, a step wave, or a similar waveform. The input end of the drive circuit 30 is coupled to the output end of the compensation voltage generating circuit 20, and the drive circuit 30 is used to generate a drive signal according to the compensation voltage to control the switching state of the switch tube. A drive control circuit proposed in the present invention effectively solves the problem of flickering during the startup phase of the LED driver or when the front-stage current suddenly increases, and does not need to increase the capacitance value of the output capacitor, thereby reducing the cost and volume of the device.

[0041] like Figure 4 As shown, an embodiment of the present invention discloses an LED driver, the LED driver includes a driving control circuit as described above, and the driving control circuit is used to control the switching state of the switch tube Q1. In one embodiment, the switch tube Q1 is built into the driving control circuit. In another embodiment, the switch tube Q1 is external to the driving control circuit. The switch tube Q1 is one of the transistors capable of realizing switching control, such as a metal oxide semiconductor field effect transistor (referred to as a MOSFET transistor), a junction field effect transistor (referred to as a JFET transistor), and an insulated gate bipolar transistor (referred to as an IGBT transistor). The driving control circuit includes a detection circuit 11, a compensation voltage generating circuit 21, and a driving circuit. The detection circuit 11 includes a comparison circuit and a dynamic detection circuit. The first input terminal of the comparison circuit is used to couple the drain of the switch tube Q1, the second input terminal of the comparison circuit is used to couple the preset voltage terminal to receive the preset voltage Vdyn, and the output terminal of the comparison circuit outputs a comparison signal. The input terminal of the dynamic detection circuit is coupled to the output terminal of the comparison circuit, and the dynamic detection circuit is used to generate a trigger signal according to the comparison signal. When the detection signal Vdrain is greater than the preset voltage Vdyn and lasts for a preset time, the dynamic detection circuit controls the trigger signal DrainH to be at a first level (e.g., a high level). When the detection signal Vdrain is less than the reference voltage, the dynamic detection circuit controls the trigger signal to be at a second level (e.g., a low level).

[0042] like Figure 4As shown, in one embodiment, the compensation voltage generating circuit 21 includes a compensation voltage regulating circuit 211, a variable resistor Rz and a resistance control circuit. The input end of the compensation voltage regulating circuit 211 is used to couple the drain of the switch tube Q1, and the output end of the compensation voltage regulating circuit 211 is used to couple the first end of the compensation capacitor Ccom. The compensation voltage regulating circuit 211 is used to filter the detection signal to obtain a processed signal. The first end of the variable resistor Rz is used to couple the second end of the compensation capacitor Ccom, and the second end of the variable resistor Rz is coupled to the ground. The first input end of the resistance control circuit is coupled to the output end of the detection circuit 11, and the resistance control circuit is used to control the resistance value of the variable resistor Rz according to the trigger signal DrainH. When the trigger signal DrainH is a first level (for example, a high level), the resistance control circuit increases the resistance value of the variable resistor Rz to a certain value. The resistance control circuit is used to gradually reduce the resistance value of the variable resistor Rz after the trigger signal DrainH changes from a first level (for example, a high level) to a second level (for example, a low level). The process of increasing or decreasing the resistance value of the variable resistor Rz may be linear or nonlinear, and may be a continuous change or a discrete change.

[0043] In another embodiment, the second input terminal of the resistance control circuit is further coupled to the first terminal of the variable resistor Rz, and the resistance control circuit is used to adjust the resistance value of the variable resistor Rz according to the voltage of the first terminal of the variable resistor Rz after the trigger signal DrainH changes from the first level (e.g., high level) to the second level (e.g., low level). As the voltage of the first terminal of the variable resistor Rz gradually decreases, the resistance control circuit gradually decreases the resistance value of the variable resistor Rz.

[0044] In another embodiment, the compensation voltage generating circuit includes a digital compensation circuit, wherein a first input terminal of the digital compensation circuit is coupled to the drain of the switch tube Q1, and a second input terminal of the digital compensation circuit is coupled to the output terminal of the detection circuit. The digital compensation circuit is used to filter the detection signal to obtain a processing signal, and to generate a compensation voltage according to the processing signal and the trigger signal. Figure 5 As shown, during the t1-t2 phase, when the detection signal Vdrain is greater than the preset voltage Vdyn, the digital compensation circuit gradually increases the compensation voltage Vcom. When the detection signal Vdrain is greater than the preset voltage Vdyn and lasts for a preset time Tdh_deb, the detection circuit controls the trigger signal DrainH to be at a first level (e.g., a high level). When the detection signal Vdrain is less than the reference voltage Vdref, the detection circuit controls the trigger signal DrainH to be at a second level (e.g., a low level). Figure 5As shown, in the t2-t3 stage, the trigger signal DrainH is at a first level. After the detection signal Vdrain is less than the reference voltage Vdref (i.e., after time t3), the detection signal Vdrain changes back and forth between the reference voltage Vdref and the reference voltage Vdref. When the trigger signal DrainH is at a first level (for example, a high level), the digital compensation circuit controls the compensation voltage to increase in a step-like manner and change with a preset amplitude. When the trigger signal DrainH changes from the first level to the second level, the digital compensation circuit gradually reduces the amplitude of the compensation voltage change until the compensation voltage Vcom stabilizes to a numerical value. In one embodiment, after the trigger signal DrainH is at the first level, the compensation voltage Vcom changes in size in the form of a sine wave, a sawtooth wave, or a step wave. Similarly, it can be based on Figure 4 The circuit structure of the present invention is implemented, and combined with Figure 5 Understand the implementation principle of the present invention, wherein Vz is the voltage of the first terminal of the variable resistor Rz, and Rz is the resistance value of the variable resistor.

[0045] An embodiment of the present invention further discloses a drive control method, which is used to control a drive control circuit. The drive control method includes:

[0046] Step S01: generating a trigger signal according to a detection signal representing the drain voltage of the switch tube, controlling the trigger signal to be at a first level when the detection signal is greater than a preset voltage for a preset time, and controlling the trigger signal to be at a second level when the detection signal is less than a reference voltage, and the preset voltage is greater than or equal to the reference voltage;

[0047] Step S02: generating a compensation voltage according to a trigger signal; when the trigger signal is at a first level, controlling the compensation voltage to increase in a stepwise manner and change with a preset amplitude, and reducing the amplitude of the compensation voltage change when the trigger signal changes from the first level to the second level; and

[0048] Step S03: generating a driving signal according to the compensation voltage to control the switch tube.

[0049] In one embodiment, the drive control circuit includes a detection circuit, a compensation voltage generating circuit and a drive circuit. The detection circuit generates a trigger signal according to a detection signal characterizing the drain voltage of the switch tube. When the detection signal is greater than a preset voltage for a preset time, the detection circuit controls the trigger signal to be at a first level. When the detection signal is less than a reference voltage, the detection circuit controls the trigger signal to be at a second level, and the preset voltage is greater than or equal to the reference voltage. The compensation voltage generating circuit generates a compensation voltage according to the trigger signal. When the trigger signal is at the first level, the compensation voltage generating circuit controls the compensation voltage to increase in a step-like manner and change with a preset amplitude, and when the trigger signal changes from the first level to the second level, the compensation voltage generating circuit reduces the amplitude of the compensation voltage change. The drive circuit generates a drive signal Vgate according to the compensation voltage to control the switching state of the switch tube.

[0050] In another embodiment, the drive control circuit includes a variable resistor, which is used to couple the compensation capacitor. The step of generating a compensation voltage according to the trigger signal also includes: when the trigger signal changes from the first level to the second level, the compensation voltage generating circuit gradually reduces the resistance value of the variable resistor.

[0051] In one embodiment, the drive control circuit includes a variable resistor, which is used to couple the compensation capacitor. The step of generating a compensation voltage according to the trigger signal also includes: when the trigger signal changes from the first level to the second level, the compensation voltage generating circuit adjusts the resistance value of the variable resistor according to the voltage at the first end of the variable resistor.

[0052] In one embodiment, the drive control circuit includes a detection circuit, a compensation voltage generating circuit and a drive circuit. The compensation voltage generating circuit includes a digital compensation circuit. The first input end of the digital compensation circuit is used to couple the drain of the switch tube, and the second input end thereof is coupled to the output end of the detection circuit. The drive control method also includes the following steps: the digital compensation circuit filters the detection signal to obtain a processing signal, and generates a compensation voltage according to the processing signal and the trigger signal. In another embodiment, the drive control method also includes the following steps: after the trigger signal is at a first level, the compensation voltage changes in size in the form of a sine wave, a sawtooth wave or a step wave.

[0053] A drive control circuit and a drive control method thereof and an LED driver proposed in the present invention effectively solve the flicker problem during the startup phase of the LED driver or when the front-stage current suddenly increases, and there is no need to increase the capacitance value of the output capacitor, thereby reducing the cost and volume of the device.

[0054] Those skilled in the art should know that the logic controls such as "high level" and "low level", "set" and "reset", "AND gate" and "OR gate", "non-inverting input terminal" and "inverting input terminal" in the logic controls involved in the specification or drawings can be interchanged or changed with each other, and the same function or purpose as the above embodiment can be achieved by adjusting the subsequent logic controls.

[0055] The description and application of the present invention here are illustrative, and it is not intended to limit the scope of the present invention to the above-mentioned embodiments. The effects or advantages involved in the specification may not be reflected in the actual experimental examples due to the uncertainty of specific condition parameters or other factors, and the effects or advantages are not used to limit the scope of the invention. The deformation and change of the embodiments disclosed here are possible, and the replacement of the embodiments and the various equivalent parts are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials and parts without departing from the spirit or essential features of the present invention. Other deformations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A drive control circuit for controlling a switch tube in an LED driver, characterized in that: The drive control circuit comprises: A detection circuit, whose input end is used to couple the switch tube to obtain a detection signal, and is used to generate a trigger signal according to the detection signal representing the drain voltage of the switch tube, and when the detection signal is greater than a preset voltage for a preset time, the trigger signal is controlled to be at a first level, and when the detection signal is less than a reference voltage, the trigger signal is controlled to be at a second level, and the preset voltage is greater than or equal to the reference voltage; a compensation voltage generating circuit, whose input terminal is coupled to the output terminal of the detection circuit, for generating a compensation voltage according to a trigger signal; when the trigger signal is at a first level, controlling the compensation voltage to increase in a stepwise manner and change with a preset amplitude, and when the trigger signal changes from the first level to a second level, reducing the amplitude of the compensation voltage change; and The driving circuit has an input end coupled to the compensation voltage generating circuit and is used to generate a driving signal according to the compensation voltage to control the switch tube.

2. The drive control circuit according to claim 1, characterized in that: The detection circuit comprises: A comparison circuit, wherein a first input terminal is coupled to the drain of the switch tube, a second input terminal is coupled to the preset voltage terminal to receive a preset voltage, and an output terminal outputs a comparison signal; and The dynamic detection circuit has an input terminal coupled to the output terminal of the comparison circuit and is used to generate a trigger signal according to the comparison signal.

3. The drive control circuit according to claim 1, characterized in that: The compensation voltage generating circuit comprises: A compensation voltage regulating circuit, whose input end is used to couple to the drain of the switch tube, and whose output end is used to couple to the first end of the compensation capacitor; and a variable resistor, a first end of which is used to couple to the second end of the compensation capacitor, and a second end of which is coupled to the ground; and The resistance control circuit has a first input terminal coupled to the output terminal of the detection circuit and is used to control the resistance value of the variable resistor according to the trigger signal.

4. The drive control circuit according to claim 3, characterized in that: The second input terminal of the resistance control circuit is coupled to the first terminal of the variable resistor. The resistance control circuit is used to adjust the resistance value of the variable resistor according to the voltage of the first terminal of the variable resistor when the trigger signal changes from the first level to the second level.

5. The drive control circuit according to claim 3, characterized in that: The resistance control circuit is used for gradually reducing the resistance value of the variable resistor when the trigger signal changes from the first level to the second level.

6. The drive control circuit according to claim 1, characterized in that: The compensation voltage generating circuit comprises: The digital compensation circuit has a first input terminal coupled to the drain of the switch tube and a second input terminal coupled to the output terminal of the detection circuit, and is used to filter the detection signal to obtain a processing signal, and generate a compensation voltage according to the processing signal and the trigger signal.

7. The drive control circuit according to claim 6, characterized in that: After the trigger signal is at the first level, the compensation voltage changes in size in a form of a sine wave, a sawtooth wave or a step wave.

8. An LED driver, characterized in that: The LED driver comprises the drive control circuit according to any one of claims 1 to 7, and the drive control circuit is used to control the switching state of the switch tube.

9. A drive control method for controlling a drive control circuit, characterized in that: The drive control method comprises: Generate a trigger signal according to a detection signal representing the drain voltage of the switch tube, control the trigger signal to be at a first level when the detection signal is greater than a preset voltage for a preset time, and control the trigger signal to be at a second level when the detection signal is less than a reference voltage, and the preset voltage is greater than or equal to the reference voltage; Generate a compensation voltage according to a trigger signal; when the trigger signal is at a first level, control the compensation voltage to increase in a stepwise manner and change with a preset amplitude, and when the trigger signal changes from the first level to a second level, reduce the amplitude of the compensation voltage change; and A driving signal is generated according to the compensation voltage to control the switch tube.

10. The driving control method according to claim 9, characterized in that: The driving control circuit includes a variable resistor, which is used to couple the compensation capacitor. The step of generating the compensation voltage according to the trigger signal also includes: gradually reducing the resistance value of the variable resistor when the trigger signal changes from the first level to the second level.

11. The driving control method according to claim 9, characterized in that: The drive control circuit includes a variable resistor, which is used to couple the compensation capacitor. The step of generating the compensation voltage according to the trigger signal also includes: adjusting the resistance value of the variable resistor according to the voltage at the first end of the variable resistor when the trigger signal changes from the first level to the second level.

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