Dimming control circuit, dimming control method and LED driving circuit

Abstract

The present invention provides a dimming control circuit, a dimming control method and an LED driving circuit. The dimming control circuit includes a negative feedback control circuit. The negative feedback control circuit is used to control the stable output of the LED driving circuit according to a dimming signal, a preset reference signal and a feedback signal, and the feedback signal is used to represent the output quantity of the LED driving circuit. The dimming control circuit further includes a bandwidth compensation circuit, and the bandwidth compensation circuit is used to output a bandwidth compensation signal according to the dimming signal. The negative feedback control circuit is coupled to the bandwidth compensation circuit, and the negative feedback control circuit is used to adjust the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal. The present invention can adaptively adjust the loop bandwidth of the dimming control circuit according to the dimming signal, so as to meet the requirements of various application scenarios for the system loop bandwidth.

Description

Technical Field

[0001] The present invention belongs to the field of electronics, relates to the field of LED driving technology, and particularly relates to a dimming control circuit, a dimming control method, and an LED driving circuit. Background Art

[0002] As one of the widely used types of lamps at present, an LED lamp is essentially a semiconductor material chip that emits light by electricity. According to the physical characteristics of the LED lamp, it needs to be driven by direct current, and the brightness of the LED lamp is related to the driving current. Figure 1 The circuit diagram of a Buck-type LED driving circuit in the prior art is shown. As Figure 1 shown, the LED driving circuit includes a rectifying and filtering circuit, an LED driving control chip, and an output stage circuit. The rectifying and filtering circuit includes a rectifier bridge and a capacitor C1. Among them, the rectifier bridge rectifies and filters the input alternating voltage AC into a DC bus voltage Vin and stores it in the capacitor C1. The output stage circuit drives the LED load according to the direct current output by the LED driving control chip.

[0003] As Figure 2 shown, it is the circuit structure of an LED driving control chip in the prior art. To obtain a relatively stable output, this technical solution uses a negative feedback loop for control. The LED driving control chip includes a proportional integral derivative control circuit (abbreviated as PID control circuit) and a driving signal generation circuit. The proportional integral derivative control circuit generates an internal reference signal according to the received reference signal and the dimming signal DIM. Among them, the internal reference signal is usually the product of the reference signal and the dimming signal DIM. At the same time, the proportional integral derivative control circuit outputs a PID control signal to the driving signal generation circuit based on the received feedback signal and the internal reference signal. The driving signal generation circuit adjusts the output of the output stage circuit according to the PID control signal, thereby realizing a closed-loop control with a reference adjustment function. However, the loop bandwidth of this LED driving circuit is fixed. Usually, in the case where the dimming signal DIM is large, a small loop bandwidth is required to ensure sufficient stability of the system. In the case where the dimming signal DIM is small, a large loop bandwidth is required to meet the requirement of the response speed of the output. If the loop bandwidth of the LED driving circuit is fixed, it is difficult to simultaneously meet these two requirements. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a dimming control circuit, a dimming control method, and an LED driving circuit, which can effectively solve the problem of the loop bandwidth requirements in different application scenarios.

[0005] The present invention provides a dimming control circuit for an LED driving circuit. The dimming control circuit includes a negative feedback control circuit. The negative feedback control circuit is used to control the stable output of the LED driving circuit according to a dimming signal, a preset reference signal, and a feedback signal, and the feedback signal is used to characterize the output quantity of the LED driving circuit. The dimming control circuit further includes a bandwidth compensation circuit, and the bandwidth compensation circuit is used to receive the dimming signal and output a bandwidth compensation signal according to the dimming signal; the negative feedback control circuit is coupled to the bandwidth compensation circuit, and the negative feedback control circuit is used to adjust the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal.

[0006] As a further improvement of the present invention, the bandwidth compensation circuit is an electronic oscillator, and the electronic oscillator is used to output a clock oscillation frequency signal that is negatively correlated with the dimming signal.

[0007] As a further improvement of the present invention, the negative feedback control circuit adjusts its own counting clock according to the clock oscillation frequency signal.

[0008] As a further improvement of the present invention, the negative feedback control circuit is a proportional-integral-derivative control circuit.

[0009] As a further improvement of the present invention, the dimming control circuit further includes:

[0010] A comparison circuit, whose first input terminal receives the preset reference signal, whose second input terminal receives the feedback signal, and whose output terminal is respectively coupled to the bandwidth compensation circuit and the proportional-integral-derivative control circuit, and is used to generate an error signal between the preset reference signal and the feedback signal.

[0011] As a further improvement of the present invention, the dimming control circuit further includes:

[0012] A multiplier, whose first input terminal receives the dimming signal and whose second input terminal receives the preset reference signal; and

[0013] A comparison circuit, whose first input terminal is coupled to the output terminal of the multiplier, whose second input terminal receives the feedback signal, and whose output terminal is coupled to the proportional-integral-derivative control circuit, and is used to generate an error signal between the product of the dimming signal and the preset reference signal and the feedback signal.

[0014] As a further improvement of the present invention, the negative feedback control circuit is used to control the loop bandwidth to be inversely proportional to the dimming signal.

[0015] As a further improvement of the present invention, the dimming control circuit further includes:

[0016] A driving signal generating circuit, coupled to the output end of the negative feedback control circuit, is configured to generate a driving signal for driving a first transistor to control the output of the LED driving circuit.

[0017] The present invention provides an LED driving circuit, which includes an input circuit, a driving control circuit, and an output circuit. The input circuit receives an input voltage, and the output circuit is configured to drive an LED load. The driving control circuit includes any one of the dimming control circuits described above.

[0018] The present invention provides a dimming control method for an LED driving circuit, which includes:

[0019] Receiving a dimming signal and outputting a bandwidth compensation signal according to the dimming signal; and

[0020] Adjusting the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal.

[0021] As a further improvement of the present invention, the step of outputting a bandwidth compensation signal according to the dimming signal includes: outputting a clock oscillation frequency signal that is negatively correlated with the dimming signal according to the dimming signal.

[0022] As a further improvement of the present invention, the step of adjusting the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal includes: adjusting the counting clock of the negative feedback control circuit according to the clock oscillation frequency signal, and the counting clock is positively correlated with the clock oscillation frequency signal.

[0023] The present invention provides a dimming control circuit, a dimming control method, and an LED driving circuit. The dimming control circuit includes a negative feedback control circuit and a bandwidth compensation circuit. The bandwidth compensation circuit generates a bandwidth compensation signal according to the dimming signal, thereby compensating the loop bandwidth of the dimming control circuit, and can effectively control the loop bandwidth of the dimming control circuit to be negatively correlated with the dimming signal. The present invention can adaptively adjust the loop bandwidth of the dimming control circuit according to the dimming signal, so as to meet the requirements of various application scenarios for the system loop bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Shows a schematic circuit diagram of an LED driving circuit of the prior art.

[0025] Figure 2 Shows a schematic circuit diagram of an LED driving control chip of the prior art.

[0026] Figure 3 Shows a schematic circuit diagram of a dimming control circuit according to an embodiment of the present invention.

[0027] Figure 4 The schematic circuit diagram of an LED driving circuit according to an embodiment of the present invention is shown.

[0028] Figure 5 The schematic circuit diagram of an LED driving circuit according to an embodiment of the present invention is shown. Detailed implementation manners

[0029] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] In order to further understand the present invention, the preferred implementation manners of the present invention will be described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0031] The description of this part only focuses on several typical embodiments, and the present invention is not limited to the scope described in the embodiments. The mutual replacement of the same or similar prior art means and some technical features in the embodiments is also within the scope of the description and protection of the present invention.

[0032] "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 electrical conduction medium, which may have parasitic inductance or parasitic capacitance; indirect connection may also include a connection through other active devices or passive devices on the basis of achieving the same or similar functional purposes, such as a connection through a circuit or component such as a switch or a follower circuit. The "terminal" (such as a signal terminal) in the specification is not limited to a specific circuit port, and it can be an actual circuit connection point or an artificially selected circuit node.

[0033] Such as Figure 3As shown in the figure, an embodiment of the present invention discloses a dimming control circuit for an LED driving circuit. The dimming control circuit includes a bandwidth compensation circuit 11 and a negative feedback control circuit 12. The input end of the bandwidth compensation circuit 11 is coupled to a dimming signal terminal, and the dimming signal terminal outputs a dimming signal DIM. The bandwidth compensation circuit 11 is configured to output a bandwidth compensation signal according to the dimming signal DIM. The input end of the negative feedback control circuit 12 is coupled to the output end of the bandwidth compensation circuit 11. The negative feedback control circuit 12 is configured to adjust the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal DIM. The negative feedback control circuit 12 can use the bandwidth compensation signal to compensate the loop bandwidth to adjust the loop bandwidth of the dimming control circuit. The negative feedback control circuit 12 is also coupled to a feedback signal terminal, and the feedback signal terminal is configured to output a feedback signal characterizing the output quantity of the LED driving circuit. Wherein, the output quantity characterized by the feedback signal can be at least one of output voltage, output current or output power. In an embodiment of the present invention, the negative feedback control circuit receives the dimming signal, a preset reference signal and the feedback signal, and controls the LED driving circuit to stably output accordingly. In a specific embodiment, the stable output of the LED driving circuit can be that the output voltage remains stable, or the output current remains stable, or the output power remains stable. In another embodiment of the present invention, the negative feedback control circuit receives the bandwidth compensation signal, a preset reference signal and the feedback signal, and controls the LED driving circuit to stably output accordingly. The bandwidth compensation signal may carry a physical signal to be characterized by the dimming signal. In essence, it is still that the negative feedback control circuit is used to control the LED driving circuit to stably output according to the dimming signal, the preset reference signal and the feedback signal.

[0034] In an embodiment of the present invention, it is required to control the output quantity of the LED driving circuit to be stable at a first reference signal, and the first reference signal is equal to the product of the preset reference signal and the dimming signal DIM. Wherein, the preset reference signal is generally a fixed value, and the dimming signal DIM can be adjusted according to the actual situation, so as to realize the adjustable control of the output quantity of the LED driving circuit through adjustable reference. Through the adjustment and control of the negative feedback control circuit in the dimming control circuit, when the feedback signal approaches the product of the preset reference signal and the dimming signal DIM, the LED driving circuit maintains a stable output. The present invention does not limit that the first reference signal is equal to the product of the preset reference signal and the dimming signal DIM. The first reference signal can be obtained by performing an operation on the preset reference signal and the dimming signal DIM, that is, only the adjustable control of the first reference signal needs to be realized.

[0035] In an embodiment of the present invention, when the dimming signal increases, the loop bandwidth of the dimming control circuit can be adaptively reduced to ensure sufficient stability of the LED driving circuit. When the dimming signal decreases, the loop bandwidth of the dimming control circuit can be adaptively increased to meet the requirements of the dynamic response speed. The present invention can adaptively adjust the loop bandwidth of the dimming control circuit according to the dimming signal, so as to meet the requirements of the system loop bandwidth in various application scenarios.

[0036] In an embodiment of the present invention, the dimming control circuit further includes an output control circuit 13, and the output control circuit 13 is used to control the output of the LED driving circuit. Among them, the output control circuit 13 includes a driving signal generating circuit 131. In another embodiment, the output control circuit 13 further includes a first transistor. The driving signal generating circuit 131 is respectively coupled to the output terminal of the feedback control circuit 12 and the first transistor, and the driving signal generating circuit 131 is used to generate a driving signal for driving the first transistor to control the output of the LED driving circuit.

[0037] In an embodiment of the present invention, the bandwidth compensation circuit is an electronic oscillator, and the electronic oscillator is used to output a clock oscillation frequency signal that is negatively correlated with the dimming signal. In a specific embodiment, the electronic oscillator may be a voltage-controlled oscillator (referred to as a VCO oscillator), and the voltage-controlled oscillator outputs a clock oscillation frequency signal that is negatively correlated with the dimming signal according to the dimming signal. When the dimming signal is large, the frequency of the clock oscillation frequency signal is small; when the dimming signal is small, the frequency of the clock oscillation frequency signal is large. In an embodiment, the voltage-controlled oscillator outputs a clock oscillation frequency signal that is inversely proportional to the dimming signal. The dimming signal can be an analog quantity, or a duty cycle or density ratio of a digital quantity.

[0038] In an embodiment of the present invention, the output terminal of the electronic oscillator is coupled to the input terminal of the negative feedback control circuit, and the negative feedback control circuit adjusts its counting clock according to the clock oscillation frequency signal. When the dimming signal increases, the frequency of the clock oscillation frequency signal output by the electronic oscillator decreases, and the negative feedback control circuit lowers its counting clock according to the clock oscillation frequency signal, thereby reducing the loop bandwidth of the dimming control circuit, so sufficient stability of the LED driving circuit can be ensured. When the dimming signal decreases, the frequency of the clock oscillation frequency signal output by the electronic oscillator increases, and the negative feedback control circuit raises its counting clock according to the clock oscillation frequency signal, thereby increasing the loop bandwidth of the dimming control circuit, so the requirements of the dynamic response speed can be met.

[0039] In an embodiment of the present invention, the dimming control circuit includes a bandwidth compensation circuit and a negative feedback control circuit. The input end of the bandwidth compensation circuit is coupled to the dimming signal end, and the dimming signal end outputs a dimming signal. The bandwidth compensation circuit is configured to output a bandwidth compensation signal according to the dimming signal. The input end of the negative feedback control circuit is coupled to the output end of the bandwidth compensation circuit. The negative feedback control circuit is configured to adjust the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is inversely proportional to the dimming signal.

[0040] As Figure 4 shown, an embodiment of the present invention provides an LED driving circuit. The LED driving circuit includes an input circuit, a driving control circuit, and an output circuit. The LED driving circuit provided in this embodiment is a linear driving dimming circuit. In another embodiment, the LED driving circuit may be a switching type driving dimming circuit. As Figure 4 shown, the input circuit includes a rectifier bridge circuit. The input circuit is configured to receive an input voltage and generate direct current. The input end of the output circuit is coupled to the output end of the driving control circuit, and the output end of the output circuit is coupled to the LED load. The output circuit is configured to drive the LED load. The driving control circuit may include a dimming control circuit, a protection circuit, etc. The dimming control circuit is configured to control the output of the output circuit so that the output of the output circuit meets the requirements of the actual usage scenario, thereby enabling the LED load to operate normally. The protection circuit is configured to switch to the protection mode in a timely manner when the operating state of the driving control circuit is abnormal to protect the driving control circuit from damage. As Figure 4 shown, the dimming control circuit includes a VCO oscillator 21 and a PID control circuit 22. The input end of the VCO oscillator 21 is coupled to the dimming signal end, and the dimming signal end outputs a dimming signal DIM. The VCO oscillator 21 is configured to output a bandwidth compensation signal according to the dimming signal DIM. Specifically, the VCO oscillator 21 outputs a clock oscillation frequency signal that is negatively correlated with the dimming signal DIM according to the dimming signal DIM. The input end of the PID control circuit 22 is coupled to the output end of the VCO oscillator 21. The PID control circuit 22 adjusts its own counting clock Clk according to the clock oscillation frequency signal. When the dimming signal DIM increases, the frequency of the clock oscillation frequency signal output by the VCO oscillator 21 decreases. The PID control circuit 22 reduces its own counting clock Clk according to the clock oscillation frequency signal, thereby reducing the loop bandwidth of the dimming control circuit. Therefore, sufficient stability of the LED driving circuit can be ensured. When the dimming signal DIM decreases, the frequency of the clock oscillation frequency signal output by the VCO oscillator 21 increases. The PID control circuit 22 increases its own counting clock Clk according to the clock oscillation frequency signal, thereby increasing the loop bandwidth of the dimming control circuit. Therefore, the requirement of the dynamic response speed can be met.

[0041] In an embodiment of the present invention, the PID control circuit 22 is used to adjust the loop bandwidth of the dimming control circuit according to the clock oscillation frequency signal to ensure that the loop bandwidth is inversely proportional to the dimming signal DIM. Based on this, the following specific embodiment can be given. The VCO oscillator 21 outputs a clock oscillation frequency signal according to the dimming signal DIM. The PID control circuit 22 adjusts its own counting clock Clk according to the clock oscillation frequency signal to ensure that the counting clock Clk = Fvco / DIM, so as to adaptively adjust the loop bandwidth of the dimming control circuit. Wherein, Fvco is the clock oscillation frequency signal initially set by the VCO oscillator. The loop bandwidth BW of the dimming control circuit satisfies BW = A*Clk, and A is a constant introduced by the output control.

[0042] In an embodiment of the present invention, the dimming control circuit further includes a comparison circuit and a multiplier. The first input terminal of the multiplier receives the dimming signal DIM, and the second input terminal of the multiplier receives the preset reference voltage Vref. The product of the dimming signal DIM and the preset reference voltage Vref can be obtained through the multiplier. The comparison circuit includes an error amplifier 24. The non-inverting input terminal of the error amplifier 24 is coupled to the output terminal of the multiplier, the inverting input terminal of the error amplifier 24 is coupled to the feedback signal terminal, and the output terminal of the error amplifier 24 is coupled to the PID control circuit 22. In this embodiment, the feedback signal terminal is used to output a feedback signal Vcs representing the output quantity of the LED driving circuit, and the feedback signal Vcs can represent the output current of the LED driving circuit. The error amplifier 24 is used to output an error signal between the product of the dimming signal DIM and the preset reference voltage Vref and the feedback signal Vcs. The input-output relationship of the PID control circuit is: Dout = A*Fvco / DIM*(Vref*DIM - Vcs)*t. Wherein, the error signal at the input terminal of the PID control circuit is Vref*DIM - Vcs, the output quantity of the PID control circuit is Dout, and A is a constant introduced by the output control. Thus, the system transfer function H = Dout / (Vref*DIM - Vcs) = A*Fvco / DIM*t. From the perspective of the PID control principle (in the time domain), the effect of the integral unit in the PID control circuit is that the output quantity Dout of the PID control circuit is proportional to the time integral of the error signal. Dout = A*Fvco / DIM*t. Except for the term of time t, all other terms can be equivalently regarded as the coefficient of the PID integral unit, and DIM changes the coefficient of the PID integral unit. From the perspective of the signal system (in the frequency domain), Dout = Fvco / DIM*t, and Fvco / DIM can be used as the loop bandwidth of the dimming control circuit. When the dimming signal DIM is changed, the loop bandwidth of the dimming control circuit is also adaptively adjusted.

[0043] Such as Figure 4As shown, in an embodiment of the present invention, the dimming control circuit further includes a drive signal generation circuit 231. The input end of the drive signal generation circuit 231 is coupled to the output end of the PID control circuit 22, and the output end of the drive signal generation circuit 231 is coupled to the control end of the first transistor Q. The drive signal generation circuit 231 is used to generate a drive signal for driving the first transistor Q to control the output of the LED drive circuit.

[0044] As Figure 5 shown, in an embodiment of the present invention, the dimming control circuit includes a VCO oscillator 31 and a PID control circuit 32. The input end of the VCO oscillator 31 receives a dimming signal DIM, and the VCO oscillator 31 is used to output a bandwidth compensation signal according to the dimming signal DIM. Specifically, the VCO oscillator 31 outputs a clock oscillation frequency signal that is negatively correlated with the dimming signal DIM according to the dimming signal DIM. The input end of the PID control circuit 32 is coupled to the output end of the VCO oscillator 31, and the PID control circuit 32 adjusts its own counting clock Clk according to the clock oscillation frequency signal.

[0045] The dimming control circuit further includes a comparison circuit. The comparison circuit includes an error amplifier 34. The non-inverting input end of the error amplifier 34 receives a preset reference voltage Vref, the inverting input end of the error amplifier 34 receives a feedback signal Vcs, and the output end of the error amplifier 34 is coupled to the PID control circuit 32. The feedback signal Vcs can represent the output current of the LED drive circuit. The error amplifier 34 is used to output an error signal between the preset reference voltage Vref and the feedback signal Vcs. The VCO oscillator receives the error signal and combines it with the dimming signal DIM, and transmits the above signals to the counting clock end of the PID control circuit in the form of a clock oscillation frequency signal. Therefore, the PID control circuit can obtain signals such as a bandwidth compensation signal, an error signal, and a dimming signal DIM by receiving the clock oscillation frequency signal, and further realize bandwidth compensation and output control. In an embodiment of the present invention, the dimming control circuit further includes a drive signal generation circuit 331. The input end of the drive signal generation circuit 331 is coupled to the output end of the PID control circuit 32, and the output end of the drive signal generation circuit 331 is coupled to the control end of the first transistor Q. The drive signal generation circuit 331 is used to generate a drive signal for driving the first transistor Q to control the output of the LED drive circuit.

[0046] An embodiment of the present invention discloses a dimming control method for an LED drive circuit, which includes:

[0047] S1. Receiving a dimming signal and outputting a bandwidth compensation signal according to the dimming signal; and

[0048] S2. Adjusting the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal.

[0049] The control process is specifically as follows: The bandwidth compensation circuit receives a dimming signal and outputs a bandwidth compensation signal according to the dimming signal. The negative feedback control circuit adjusts the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal.

[0050] In an embodiment of the present invention, the step of outputting a bandwidth compensation signal according to the dimming signal includes: outputting a clock oscillation frequency signal that is negatively correlated with the dimming signal according to the dimming signal. The bandwidth compensation circuit is specifically an electronic oscillator, and the electronic oscillator outputs a clock oscillation frequency signal that is negatively correlated with the dimming signal according to the dimming signal.

[0051] In an embodiment of the present invention, the step of adjusting the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal includes: adjusting the counting clock of the negative feedback control circuit according to the clock oscillation frequency signal, and the counting clock is positively correlated with the clock oscillation frequency signal. That is, the negative feedback control circuit adjusts its own counting clock according to the clock oscillation frequency signal to ensure that the counting clock is positively correlated with the clock oscillation frequency signal.

[0052] The present invention provides a dimming control circuit, a dimming control method, and an LED driving circuit. Among them, the dimming control circuit includes a negative feedback control circuit and a bandwidth compensation circuit. The bandwidth compensation circuit generates a bandwidth compensation signal according to the dimming signal, thereby compensating the loop bandwidth of the dimming control circuit, and can effectively control the loop bandwidth of the dimming control circuit to be negatively correlated with the dimming signal. The present invention can adaptively adjust the loop bandwidth of the dimming control circuit according to the dimming signal, so as to meet the requirements of various application scenarios for the system loop bandwidth.

[0053] The above description and application of the present invention are illustrative, and it is not intended to limit the scope of the present invention to the above embodiments. The related descriptions of the effects or advantages involved in the embodiments may not be reflected in the experimental examples due to the uncertainty of specific condition parameters, and are not used to limit the embodiments. The deformations and changes of the disclosed embodiments here are possible, and the substitutions and equivalents of various components for those of ordinary skill in the art are well known. Those skilled in the art should clearly understand that without departing from the spirit or essential characteristics of the present invention, the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and parts. Without departing from the scope and spirit of the present invention, other deformations and changes can be made to the disclosed embodiments here.

Claims

1. A dimming control circuit for an LED driving circuit, the dimming control circuit including a negative feedback control circuit for controlling the stable output of the LED driving circuit according to a dimming signal, a preset reference signal, and a feedback signal, the feedback signal being used to represent the output quantity of the LED driving circuit. Characterized in that the dimming control circuit further includes a bandwidth compensation circuit for receiving the dimming signal and outputting a bandwidth compensation signal according to the dimming signal; the negative feedback control circuit is coupled to the bandwidth compensation circuit, and the negative feedback control circuit is used to adjust the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal; the bandwidth compensation circuit includes an electronic oscillator for outputting a clock oscillation frequency signal negatively correlated with the dimming signal.

2. The dimming control circuit according to claim 1, Characterized in that the negative feedback control circuit adjusts its own counting clock according to the clock oscillation frequency signal.

3. The dimming control circuit according to claim 1, Characterized in that the negative feedback control circuit is a proportional integral derivative control circuit.

4. The dimming control circuit according to claim 3, Characterized in that the dimming control circuit further includes: a comparison circuit, its first input terminal receives the preset reference signal, its second input terminal receives the feedback signal, and its output terminal is respectively coupled to the bandwidth compensation circuit and the proportional integral derivative control circuit for generating an error signal between the preset reference signal and the feedback signal.

5. The dimming control circuit according to claim 3, Characterized in that the dimming control circuit further includes: a multiplier, its first input terminal receives the dimming signal, its second input terminal receives the preset reference signal; and a comparison circuit, its first input terminal is coupled to the output terminal of the multiplier, its second input terminal receives the feedback signal, and its output terminal is coupled to the proportional integral derivative control circuit for generating an error signal between the product of the dimming signal and the preset reference signal and the feedback signal.

6. The dimming control circuit according to claim 1, Characterized in that the negative feedback control circuit is used to control the loop bandwidth to be inversely proportional to the dimming signal.

7. The dimming control circuit according to claim 1, Characterized in that the dimming control circuit further includes: a drive signal generation circuit, coupled to the output terminal of the negative feedback control circuit, for generating a drive signal for driving a first transistor to control the output quantity of the LED driving circuit.

8. An LED driving circuit, the LED driving circuit including an input circuit, a drive control circuit, and an output circuit, the input circuit receiving an input voltage, the output circuit being used to drive an LED load, Characterized in that the drive control circuit includes the dimming control circuit according to any one of claims 1-7.

9. A dimming control method for the LED driving circuit according to claim 8, Characterized in that it includes: receiving a dimming signal and outputting a bandwidth compensation signal according to the dimming signal; and Adjust the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal.

10. The dimming control method according to claim 9, wherein, the step of outputting a bandwidth compensation signal according to the dimming signal includes: output a clock oscillation frequency signal that is negatively correlated with the dimming signal according to the dimming signal.

11. The dimming control method according to claim 10, wherein, the step of adjusting the loop bandwidth of the dimming control circuit according to the bandwidth compensation signal to ensure that the loop bandwidth is negatively correlated with the dimming signal includes: adjust the counting clock of the negative feedback control circuit according to the clock oscillation frequency signal, and the counting clock is positively correlated with the clock oscillation frequency signal.

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