Driving control circuit, driving control method thereof and LED driving circuit

Abstract

The invention provides a drive control circuit, a drive control method thereof and an LED drive circuit. The drive control circuit comprises a sampling circuit, a threshold generation circuit and a control circuit. The sampling circuit is used for acquiring a sampling peak signal and a sampling valley signal in a preset period according to the sampling signal representing the compensation voltage. The threshold value generation circuit is coupled to the sampling circuit and is used for generating a first threshold value and a second threshold value according to the sampling peak value signal and the sampling valley value signal. And the input end of the control circuit is coupled with the output end of the threshold generation circuit, and the control circuit is used for generating a loop bandwidth control signal according to the sampling signal so as to adjust the ripple-removed loop bandwidth. And when the sampling signal meets a preset condition, the control circuit controls to increase the ripple removal loop bandwidth. According to the sampling circuit, the threshold generation circuit and the control circuit provided by the invention, low-frequency ripples of the LED driving circuit during duty ratio adjustment can be effectively solved, and the system has better dynamic performance and steady-state performance.

Description

Technical Field

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

[0002] LED lamps are widely used in the field of lighting due to their advantages of energy saving, environmental protection, good color rendering, etc. In specific circuit applications, LED driving circuits 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 flash-free circuit design is required. Figure 1 As shown, the implementation principle is to filter the drain voltage Vdrain to convert it into a stable compensation voltage Vcom, and then pass it through the constant current loop amplifier circuit AMP. The output signal of the constant current loop amplifier circuit AMP is used to control the main power tube to achieve low ripple of the load current I LED. In order to further reduce the ripple in the load current I LED, the bandwidth of the compensation voltage regulation circuit is very slow, which will lead to the problem of poor dynamic performance of the ripple removal system of the LED drive circuit.

[0004] Combination Figure 1-2 In an example, when the front-stage current Iout changes, the load current ILED is affected by the adaptive reference regulation loop and changes relatively slowly, which will cause the capacitor current Icap and the drain voltage Vdrain to change. The front-stage energy change is reflected in the drain voltage Vdrain more quickly, but the load current ILED is affected by the compensation voltage Vcom loop and reacts more slowly. Among them, the front-stage duty cycle Duty controls the front-stage current Iout, Iout = k*Duty, k is a coefficient. This will eventually cause the compensation voltage Vcom and the load current ILED to appear as follows Figure 2 An optimization solution is to make the regulation loop faster by reducing the capacitance of the compensation capacitor Ccom, but this method will result in larger steady-state ripple.

[0005] 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

[0006] 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 drive circuit.

[0007] According to one aspect of the present invention, a drive control circuit is disclosed. The drive control circuit is used to control an LED drive circuit. The drive control circuit includes:

[0008] A sampling circuit, whose input terminal is used to receive a sampling signal representing a compensation voltage, and is used to obtain a sampling peak signal and a sampling valley signal within a preset period according to the sampling signal;

[0009] A threshold generation circuit, whose input terminal is coupled to the output terminal of the sampling circuit, is used to generate a first threshold and a second threshold according to the sampling peak signal and the sampling valley signal; in a steady state, the first threshold is greater than the sampling peak signal, and the second threshold is less than the sampling valley signal; and

[0010] The control circuit has an input end coupled to the output end of the threshold generation circuit, and is used to generate a loop bandwidth control signal according to the sampling signal to adjust the de-ripple loop bandwidth; when the sampling signal is greater than the first threshold or less than the second threshold in one or several consecutive compensation voltage cycles, the control circuit controls to increase the de-ripple loop bandwidth.

[0011] In one embodiment, the threshold generation circuit is used to obtain a sampling weighted signal according to the sampling peak signal and the sampling valley signal, generate a first threshold according to the sampling peak signal and the sampling weighted signal, and generate a second threshold according to the sampling valley signal and the sampling weighted signal.

[0012] In one embodiment, the sampled weighted signal is a sampled average signal.

[0013] In one embodiment, the threshold generating circuit includes a filtering circuit, the filtering circuit is used to generate a first filtering signal according to a sampled peak signal, and to generate a second filtering signal according to a sampled valley signal; the threshold generating circuit is used to generate a sampled average signal according to the sampled peak signal and the sampled valley signal, and to generate a first threshold according to the first filtering signal and the sampled average signal, and to generate a second threshold according to the second filtering signal and the sampled average signal.

[0014] In one embodiment, the threshold generation circuit further includes:

[0015] A signal processing circuit, whose input end receives the sampling peak signal and the sampling valley signal respectively, is used to generate a sampling average signal according to the sampling peak signal and the sampling valley signal, and to perform gain on the sampling average signal to generate a gain signal;

[0016] A first operation circuit, a first input terminal of which is coupled to the filter circuit, and a second input terminal of which is coupled to the signal processing circuit, for adding the first filter signal and the gain signal to obtain a first threshold value; and

[0017] The second operation circuit has a first input terminal coupled to the filter circuit and a second input terminal coupled to the signal processing circuit, and is used for subtracting the second filter signal from the gain signal to obtain a second threshold.

[0018] In one embodiment, the sampling circuit comprises:

[0019] A first sampling circuit, whose input terminal is used to receive a sampling signal representing the compensation voltage, and is used to obtain a peak value within a preset period according to the sampling signal to generate a sampling peak signal; and

[0020] The second sampling circuit has an input end for receiving a sampling signal representing the compensation voltage, and is used for acquiring a valley value within a preset period according to the sampling signal to generate a sampling valley value signal.

[0021] In one embodiment, the first sampling circuit comprises:

[0022] A first operational amplifier circuit, wherein a first input terminal of the operational amplifier circuit is used to receive a sampling signal;

[0023] A first diode, an anode of which is coupled to the output terminal of the first operational amplifier circuit, and a cathode of which is coupled to the second input terminal of the first operational amplifier circuit;

[0024] A first switch, a first end of which is coupled to a first input end of the first operational amplifier circuit;

[0025] A first capacitor, a first end of which is coupled to the second end of the first switch, and a second end of which is coupled to the ground;

[0026] A second switch, a first terminal of which is coupled to the first terminal of the first capacitor; and

[0027] The second capacitor has a first terminal coupled to the second terminal of the second switch and a second terminal coupled to the ground.

[0028] In one embodiment, the second sampling circuit comprises:

[0029] A second operational amplifier circuit, wherein a first input terminal of the second operational amplifier circuit is used to receive a sampling signal;

[0030] A second diode, an anode of which is coupled to the second input terminal of the second operational amplifier circuit, and a cathode of which is coupled to the output terminal of the second operational amplifier circuit;

[0031] A third switch, a first end of which is coupled to the first input end of the second operational amplifier circuit;

[0032] A third capacitor, a first end of which is coupled to the second end of the third switch, and a second end of which is coupled to the ground;

[0033] a fourth switch, a first terminal of which is coupled to the first terminal of the third capacitor; and

[0034] A fourth capacitor has a first terminal coupled to the second terminal of the fourth switch and a second terminal coupled to the ground.

[0035] In one embodiment, the control circuit comprises:

[0036] A first comparison circuit, a first input terminal of which is coupled to the sampling signal, and a second input terminal of which is coupled to the first threshold;

[0037] A second comparison circuit, a first input terminal of which is coupled to the second threshold, and a second input terminal of which is coupled to the sampling signal; and

[0038] The OR gate has a first input terminal coupled to the output terminal of the first comparison circuit, a second input terminal coupled to the output terminal of the second comparison circuit, and an output terminal outputting an OR gate output signal.

[0039] In one embodiment, the control circuit further includes:

[0040] The de-jitter time control circuit has its input terminals respectively coupled to the first comparison circuit and the second comparison circuit, and its output terminals respectively coupled to the OR gate, for preventing false triggering of the dynamic adjustment of the de-ripple loop bandwidth.

[0041] In one embodiment, the control circuit is used to control the bandwidth of the de-ripple loop to recover to a steady-state value when no sampling signal is greater than a first threshold or less than a second threshold within n compensation voltage cycles, n≥2.

[0042] According to another aspect of the present invention, an LED driving circuit is disclosed, wherein the LED driving circuit comprises the driving control circuit as described in any one of the above items.

[0043] 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:

[0044] Acquire a sampling signal representing the compensation voltage, and acquire a sampling peak signal and a sampling valley signal within a preset period according to the sampling signal;

[0045] Generate a first threshold and a second threshold according to the sampled peak signal and the sampled valley signal; in a steady state, the first threshold is greater than the sampled peak signal, and the second threshold is less than the sampled valley signal; and

[0046] A loop bandwidth control signal is generated according to the sampling signal, the first threshold and the second threshold to adjust the de-ripple loop bandwidth; when the sampling signal is greater than the first threshold or less than the second threshold in one or several consecutive compensation voltage cycles, the de-ripple loop bandwidth is controlled to increase.

[0047] In one embodiment, the step of generating the first threshold and the second threshold according to the sampled peak signal and the sampled valley signal includes: obtaining a sampled weighted signal according to the sampled peak signal and the sampled valley signal, generating the first threshold according to the sampled peak signal and the sampled weighted signal, and generating the second threshold according to the sampled valley signal and the sampled weighted signal.

[0048] In one embodiment, the sampled weighted signal is a sampled average signal.

[0049] In one embodiment, the step of generating the first threshold and the second threshold according to the sampled peak signal and the sampled valley signal comprises:

[0050] Generate a sampled average signal according to the sampled peak value signal and the sampled valley value signal, and perform gain on the sampled average signal to generate a gain signal;

[0051] The first filtered signal and the gain signal are added to obtain a first threshold; and the second filtered signal and the gain signal are subtracted to obtain a second threshold.

[0052] In one embodiment, the drive control method further includes:

[0053] When the sampling signal does not exceed the first threshold or is less than the second threshold within n compensation voltage cycles, the bandwidth of the ripple removal loop is controlled to recover to a steady-state value, n≥2.

[0054] The present invention proposes a driving control circuit and a driving control method thereof and an LED driving circuit. The driving control circuit is used to control the LED driving circuit, and the driving control circuit includes a sampling circuit, a threshold generating circuit and a control circuit. The input end of the sampling circuit is used to receive a sampling signal representing a compensation voltage, and the sampling circuit is used to obtain a sampling peak signal and a sampling valley signal within a preset period according to the sampling signal. The input end of the threshold generating circuit is coupled to the output end of the sampling circuit, and the threshold generating circuit is used to generate a first threshold and a second threshold according to the sampling peak signal and the sampling valley signal. In a steady state, the first threshold is greater than the sampling peak signal, and the second threshold is less than the sampling valley signal. The input end of the control circuit is coupled to the output end of the threshold generating circuit, and the control circuit is used to generate a loop bandwidth control signal according to the sampling signal to adjust the de-ripple loop bandwidth. When the sampling signal is greater than the first threshold or less than the second threshold in one or several consecutive compensation voltage cycles, the control circuit controls to increase the de-ripple loop bandwidth. The sampling circuit, the threshold generating circuit and the control circuit proposed by the present invention can effectively solve the low-frequency ripple of the LED driving circuit when the duty cycle is adjusted, and the system has better dynamic performance and steady-state performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] 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:

[0056] Figure 1 A circuit structure schematic diagram of a LED driving circuit in the prior art is shown;

[0057] Figure 2A signal waveform schematic diagram of an LED driving circuit in the prior art is shown;

[0058] Figure 3 A schematic diagram of the circuit structure of a drive control circuit according to an embodiment of the present invention is shown;

[0059] Figure 4 A schematic diagram of the circuit structure of a drive control circuit according to another embodiment of the present invention is shown;

[0060] Figure 5 A schematic diagram of signal waveforms of an LED driving circuit according to an embodiment of the present invention is shown;

[0061] Figure 6 A schematic diagram of signal waveforms of an LED driving circuit according to another embodiment of the present invention is shown;

[0062] Figure 7 FIG. 4 is a schematic diagram showing signal waveforms of an LED driving circuit according to yet another embodiment of the present invention. DETAILED DESCRIPTION

[0063] 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.

[0064] 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.

[0065] "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.

[0066] The present invention discloses a drive control circuit, which is used to control an LED drive circuit to achieve a lighting function. In one embodiment, Figure 3 As shown, the drive control circuit includes a sampling circuit 10, a threshold generation circuit 20 and a control circuit 30. The input end of the sampling circuit 10 is used to receive a sampling signal representing the compensation voltage, and the sampling circuit 10 is used to obtain a sampling peak signal and a sampling valley signal within a preset period according to the sampling signal. The sampling signal is positively correlated with the compensation voltage. In one embodiment, the sampling signal is proportional to the compensation voltage. In another embodiment, the sampling signal is equal to the compensation voltage Vcom. In another embodiment, the drain voltage is positively correlated with the compensation voltage, the sampling signal is positively correlated with the drain voltage, or the sampling signal is the drain voltage. Among them, the drain voltage is the drain voltage of the main power tube. The sampling circuit 10 obtains a sampling peak signal within a preset period, and obtains a sampling valley signal within a preset period, and the preset period is greater than the compensation voltage period. The compensation voltage period can be determined based on the previous stage current. As Figure 3 As shown, the input end of the threshold generating circuit 20 is coupled to the output end of the sampling circuit 10, and the threshold generating circuit 20 is used to generate a first threshold and a second threshold according to the sampled peak signal and the sampled valley signal. In one embodiment, when the sampled peak signal and the sampled valley signal both increase, the first threshold and the second threshold both increase. When the sampled peak signal and the sampled valley signal both decrease, the first threshold and the second threshold both decrease. When the LED driving circuit tends to a steady state, the difference between the first threshold and the second threshold decreases. In the steady state, the first threshold is greater than the sampled peak signal, and the second threshold is less than the sampled valley signal. At the same time, the first threshold is greater than the second threshold. The input end of the control circuit 30 is coupled to the output end of the threshold generating circuit 20, and the control circuit 30 is used to generate a loop bandwidth control signal according to the sampling signal to adjust the de-ripple loop bandwidth. When a sampling signal is greater than a first threshold or less than a second threshold in one or several consecutive compensation voltage cycles, the control circuit controls to increase the bandwidth of the de-ripple loop. By timely adjusting the bandwidth of the de-ripple loop, the low-frequency ripple of the LED driving circuit during duty cycle adjustment is effectively solved, and the system has better dynamic performance and steady-state performance.

[0067] In one embodiment, the threshold generation circuit obtains a sampling weighted signal according to the sampling peak signal and the sampling valley signal. The sampling weighted signal is the sum of the weighted sampling peak signal and the weighted sampling valley signal. The threshold generation circuit generates a first threshold according to the sampling peak signal and the sampling weighted signal, and generates a second threshold according to the sampling valley signal and the sampling weighted signal. In another embodiment, the sampling weighted signal is a sampling average signal, and the sampling average signal is the average value of the sampling peak signal and the sampling valley signal.

[0068] In another embodiment, the threshold generation circuit includes a filtering circuit, the filtering circuit is used to generate a first filtering signal according to the sampled peak signal, and to generate a second filtering signal according to the sampled valley signal. The threshold generation circuit is used to generate a sampled average signal according to the sampled peak signal and the sampled valley signal, and to generate a first threshold according to the first filtering signal and the sampled average signal, and to generate a second threshold according to the second filtering signal and the sampled average signal.

[0069] In one embodiment, if Figure 4 As shown, the drive control circuit includes a sampling circuit 11, a threshold generation circuit 21 and a control circuit 31. The sampling circuit 11 includes a first sampling circuit and a second sampling circuit. The input end of the first sampling circuit is used to receive a sample signal Vcom, and the first sampling circuit is used to obtain a peak value within a preset period according to the sampling signal to generate a sample peak signal. The input end of the second sampling circuit is used to receive a sample signal Vcom, and the second sampling circuit is used to obtain a valley value within a preset period according to the sampling signal to generate a sample valley value signal.

[0070] The first sampling circuit includes a first operational amplifier circuit 111, a first diode D1, a first switch S1, a first capacitor C1, a second switch S2, and a second capacitor C2. The first input terminal of the first operational amplifier circuit 111 is used to receive a sampling signal Vcom. The anode of the first diode D1 is coupled to the output terminal of the first operational amplifier circuit, and the cathode of the first diode D1 is coupled to the second input terminal of the first operational amplifier circuit. The first terminal of the first switch S1 is coupled to the first input terminal of the first operational amplifier circuit. The first terminal of the first capacitor C1 is coupled to the second terminal of the first switch, and the second terminal of the first capacitor C1 is coupled to the ground. The first terminal of the second switch S2 is coupled to the first terminal of the first capacitor. The first terminal of the second capacitor C2 is coupled to the second terminal of the second switch, and the second terminal of the second capacitor C2 is coupled to the ground.

[0071] The second sampling circuit includes a second operational amplifier circuit 112, a second diode D2, a third switch S3, a third capacitor C3, a fourth switch S4 and a fourth capacitor C4. The first input terminal of the second operational amplifier circuit 112 is used to receive the sampling signal Vcom. The anode of the second diode D2 is coupled to the second input terminal of the second operational amplifier circuit, and the cathode of the second diode D2 is coupled to the output terminal of the second operational amplifier circuit. The first end of the third switch S3 is coupled to the first input terminal of the second operational amplifier circuit. The first end of the third capacitor C3 is coupled to the second end of the third switch, and the second end of the third capacitor C3 is coupled to the ground. The first end of the fourth switch S4 is coupled to the first end of the third capacitor. The first end of the fourth capacitor C4 is coupled to the second end of the fourth switch, and the second end of the fourth capacitor C4 is coupled to the ground.

[0072] like Figure 4As shown, the threshold generation circuit 21 includes a filtering circuit, a signal processing circuit 213, a first operation circuit and a second operation circuit. The filtering circuit includes a first low-pass filtering circuit 211 and a second low-pass filtering circuit 212. The input end of the first low-pass filtering circuit 211 is coupled to the sampling circuit, and the first low-pass filtering circuit 211 is used to generate a first filtering signal VcomPk according to the sampling peak signal VcomPk0. The input end of the second low-pass filtering circuit 212 is coupled to the sampling circuit, and the second low-pass filtering circuit 212 is used to generate a second filtering signal VcomVly according to the sampling valley signal VcomVly0. The input end of the signal processing circuit 213 receives the sampling peak signal VcomPk0 and the sampling valley signal VcomVly0 respectively, and the signal processing circuit 213 is used to generate a sampling average signal VcomAvg according to the sampling peak signal and the sampling valley signal, and to gain the sampling average signal to generate a gain signal VcomAvg*k, where k is a gain coefficient. The first input terminal of the first operation circuit is coupled to the first low-pass filter circuit 211, the second input terminal of the first operation circuit is coupled to the signal processing circuit, and the third input terminal of the first operation circuit is coupled to the voltage Vth. The first operation circuit is used to add the first filter signal VcomPk, the gain signal VcomAvg*k, and the voltage Vth to obtain the first threshold value VcomHth. The first input terminal of the second operation circuit is coupled to the second low-pass filter circuit 212, the second input terminal of the second operation circuit is coupled to the signal processing circuit, and the third input terminal of the second operation circuit is coupled to the voltage Vth. The second operation circuit is used to subtract the gain signal VcomAvg*k and the voltage Vth from the second filter signal VcomVly to obtain the second threshold value VcomLth.

[0073] like Figure 4 As shown, the control circuit 31 includes a first comparison circuit Cmp1, a second comparison circuit Cmp2, a de-jitter time control circuit and an OR gate. The first comparison circuit Cmp1 includes a first comparator 311. The second comparison circuit Cmp2 includes a second comparator 312. The de-jitter time control circuit includes a first de-jitter time control circuit 313 and a second de-jitter time control circuit 314. The non-inverting input terminal of the first comparator 311 is coupled to the sampling signal Vcom, and the inverting input terminal of the first comparator 311 is coupled to the first threshold value VcomHth. The non-inverting input terminal of the second comparator 312 is coupled to the second threshold value VcomLth, and the inverting input terminal of the second comparator 312 is coupled to the sampling signal Vcom. The input terminal of the first de-jitter time control circuit 313 is coupled to the output terminal of the first comparator 311. The input terminal of the second de-jitter time control circuit 314 is coupled to the output terminal of the second comparator 312. The first input terminal of the OR gate is coupled to the output terminal of the first de-bounce time control circuit 313, the second input terminal of the OR gate is coupled to the output terminal of the second de-bounce time control circuit 314, and the output terminal of the OR gate outputs the OR gate output signal ComDyn. Figure 6 As shown, in one embodiment, when the sampling signal is greater than the first threshold or less than the second threshold, the OR gate output signal ComDyn is a first level (e.g., a high level). When the sampling signal is neither greater than the first threshold nor less than the second threshold, the OR gate output signal ComDyn is a second level (e.g., a low level).

[0074] In one embodiment, the control circuit is further configured to control the bandwidth of the de-ripple loop to recover to a steady-state value when no sampling signal is greater than a first threshold or less than a second threshold within n compensation voltage cycles, where n≥2.

[0075] Combination Figure 4-5 In one embodiment, when the front-stage duty cycle Duty controls the front-stage current Iout, the front-stage current Iout changes, and low-frequency ripple appears in the compensation voltage Vcom of the LED driving circuit. The sampling circuit 11 includes a first sampling circuit and a second sampling circuit, and the first sampling circuit is used to obtain the sampling peak signal VcomPk0. The maximum value sampling circuit is formed by the first operational amplifier circuit and the first diode and other devices. After being controlled by the reset pulse signal Clear and the sampling pulse signal Sample, the switch capacitor network composed of the first switch S1, the first capacitor C1, the second switch S2 and the second capacitor C2 can obtain the peak value in the local time. The reset pulse signal Clear is used to control the switching state of the first switch and the third switch respectively. The sampling pulse signal Sample is used to control the switching state of the second switch and the fourth switch respectively. The period of the reset pulse signal Clear and the sampling pulse signal Sample is Ts, and the reset pulse signal Clear lags behind the sampling pulse signal Sample, and the preset period Ts is greater than the compensation voltage period. At the end of a preset sampling period Ts, the second switch S2 is turned on, and the signal on the first capacitor C1 is transferred to the second capacitor C2, and then the second switch S2 is turned off. After that, the first switch S1 is briefly turned on, and the voltage on the first capacitor C1 is reset to the compensation voltage Vcom, and the next cycle of sampling begins. By resetting each cycle, it can be ensured that the peak value of the compensation voltage (i.e., the sampling peak signal VcomPk0) within a preset period Ts is sampled. The sampling logic of the sampling valley signal is similar to that of the sampling peak signal, which will not be repeated here.

[0076] In one embodiment, in combination Figure 6-7, when the front-stage circuit is dimming (i.e., the duty cycle changes), it causes the front-stage current Iout to change, and the compensation voltage Vcom will change. When the compensation voltage Vcom is triggered to be greater than the first threshold value VcomHth within one or several consecutive compensation voltage cycles, the control circuit determines that it has entered the dynamic mode. At this time, the loop bandwidth control signal ComH is at a first level (for example, a high level), and the de-ripple loop bandwidth will increase. When the compensation voltage Vcom is triggered to be less than the second threshold value VcomLth within one or several consecutive compensation voltage cycles, the control circuit determines that it has entered the dynamic mode, and the de-ripple loop bandwidth BandRate will increase. In one embodiment, when the control circuit determines that it can enter the dynamic mode, the de-ripple loop bandwidth will slowly increase. When the front-stage circuit is not dimming, the front-stage current Iout does not change, and the compensation voltage Vcom remains stable. As Figure 7 As shown, if there is no sampling signal greater than the first threshold or less than the second threshold within n compensation voltage cycles, and the loop bandwidth control signal ComH is at the second level (for example, a low level), the control circuit determines that the dynamic mode can be exited, and the de-ripple loop bandwidth BandRate will slowly decrease to a steady-state value. Figure 6 The time tdeb_comdyn is the debounce time, which is used to prevent false triggering to enter the dynamic mode. Figure 7 The time tdeb_comdyn_ex is the debounce time, which is used to prevent false triggering of exiting the dynamic mode.

[0077] An embodiment of the present invention further discloses an LED driving circuit, the LED driving circuit comprising a driving control circuit as described in any one of the above items. The driving control circuit comprises a sampling circuit, a threshold generating circuit and a control circuit. The control circuit generates a loop bandwidth control signal according to a sampling signal to adjust the de-ripple loop bandwidth. When the sampling signal is greater than a first threshold or less than a second threshold in one or several consecutive compensation voltage cycles, the control circuit controls to increase the de-ripple loop bandwidth. The LED driving circuit controls the working state of the main power tube according to the compensation voltage Vcom and the current sampling signal Vcs.

[0078] An embodiment of the present invention further discloses a drive control method, which is used to control a drive control circuit, wherein the drive control circuit includes a sampling circuit, a threshold generation circuit and a control circuit. The drive control method includes:

[0079] Step S1: obtaining a sampling signal representing a compensation voltage, and obtaining a sampling peak signal and a sampling valley signal within a preset period according to the sampling signal;

[0080] Step S2: generating a first threshold and a second threshold according to the sampled peak signal and the sampled valley signal; in a steady state, the first threshold is greater than the sampled peak signal, and the second threshold is less than the sampled valley signal; and

[0081] Step S3: Generate a loop bandwidth control signal according to the sampling signal, the first threshold and the second threshold to adjust the de-ripple loop bandwidth; when the sampling signal is greater than the first threshold or less than the second threshold in one or several consecutive compensation voltage cycles, control to increase the de-ripple loop bandwidth.

[0082] In one embodiment, the step of generating the first threshold and the second threshold according to the sampled peak signal and the sampled valley signal comprises: the threshold generating circuit obtains a sampled weighted signal according to the sampled peak signal and the sampled valley signal, generates the first threshold according to the sampled peak signal and the sampled weighted signal, and generates the second threshold according to the sampled valley signal and the sampled weighted signal. In another embodiment, the sampled weighted signal is a sampled average signal.

[0083] In one embodiment, the step of generating the first threshold and the second threshold according to the sampled peak signal and the sampled valley signal includes: the threshold generation circuit generates a sampled average signal according to the sampled peak signal and the sampled valley signal, and amplifies the sampled average signal to generate a gain signal; adds the first filtered signal and the gain signal to obtain the first threshold; and subtracts the second filtered signal from the gain signal to obtain the second threshold.

[0084] In another embodiment, the drive control method further includes: when the sampling signal of the control circuit does not exceed the first threshold or is less than the second threshold within n compensation voltage cycles, controlling the de-ripple loop bandwidth to recover to a steady-state value, n≥2.

[0085] 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.

[0086] 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 an LED drive circuit, characterized in that: The drive control circuit comprises: A sampling circuit, whose input terminal is used to receive a sampling signal representing a compensation voltage, and is used to obtain a sampling peak signal and a sampling valley signal within a preset period according to the sampling signal; A threshold generation circuit, whose input terminal is coupled to the output terminal of the sampling circuit, is used to generate a first threshold and a second threshold according to the sampling peak signal and the sampling valley signal; in a steady state, the first threshold is greater than the sampling peak signal, and the second threshold is less than the sampling valley signal; and The control circuit has an input end coupled to the output end of the threshold generation circuit, and is used to generate a loop bandwidth control signal according to the sampling signal to adjust the de-ripple loop bandwidth; when the sampling signal is greater than the first threshold or less than the second threshold in one or several consecutive compensation voltage cycles, the control circuit controls to increase the de-ripple loop bandwidth.

2. The drive control circuit according to claim 1, characterized in that: The threshold generating circuit is used to obtain a sampling weighted signal according to the sampling peak signal and the sampling valley signal, generate a first threshold according to the sampling peak signal and the sampling weighted signal, and generate a second threshold according to the sampling valley signal and the sampling weighted signal.

3. The drive control circuit according to claim 2, characterized in that: The sampled weighted signal is a sampled average signal.

4. The drive control circuit according to claim 1, characterized in that: The threshold generating circuit includes a filtering circuit, which is used to generate a first filtering signal according to a sampled peak signal, and to generate a second filtering signal according to a sampled valley signal; the threshold generating circuit is used to generate a sampled average signal according to the sampled peak signal and the sampled valley signal, and to generate a first threshold according to the first filtering signal and the sampled average signal, and to generate a second threshold according to the second filtering signal and the sampled average signal.

5. The drive control circuit according to claim 4, characterized in that: The threshold generation circuit further includes: A signal processing circuit, whose input end receives the sampling peak signal and the sampling valley signal respectively, is used to generate a sampling average signal according to the sampling peak signal and the sampling valley signal, and to perform gain on the sampling average signal to generate a gain signal; A first operation circuit, a first input terminal of which is coupled to the filter circuit, and a second input terminal of which is coupled to the signal processing circuit, for adding the first filter signal and the gain signal to obtain a first threshold value; and The second operation circuit has a first input terminal coupled to the filter circuit and a second input terminal coupled to the signal processing circuit, and is used for subtracting the second filter signal from the gain signal to obtain a second threshold.

6. The drive control circuit according to claim 1, characterized in that: The sampling circuit comprises: A first sampling circuit, whose input terminal is used to receive a sampling signal representing the compensation voltage, and is used to obtain a peak value within a preset period according to the sampling signal to generate a sampling peak signal; and The second sampling circuit has an input end for receiving a sampling signal representing the compensation voltage, and is used for acquiring a valley value within a preset period according to the sampling signal to generate a sampling valley value signal.

7. The drive control circuit according to claim 6, characterized in that: The first sampling circuit comprises: A first operational amplifier circuit, wherein a first input terminal of the operational amplifier circuit is used to receive a sampling signal; A first diode, an anode of which is coupled to the output terminal of the first operational amplifier circuit, and a cathode of which is coupled to the second input terminal of the first operational amplifier circuit; A first switch, a first end of which is coupled to a first input end of the first operational amplifier circuit; A first capacitor, a first end of which is coupled to the second end of the first switch, and a second end of which is coupled to the ground; A second switch, a first terminal of which is coupled to the first terminal of the first capacitor; and The second capacitor has a first terminal coupled to the second terminal of the second switch and a second terminal coupled to the ground.

8. The drive control circuit according to claim 6, characterized in that: The second sampling circuit comprises: A second operational amplifier circuit, wherein a first input terminal of the second operational amplifier circuit is used to receive a sampling signal; A second diode, an anode of which is coupled to the second input terminal of the second operational amplifier circuit, and a cathode of which is coupled to the output terminal of the second operational amplifier circuit; A third switch, a first end of which is coupled to the first input end of the second operational amplifier circuit; A third capacitor, a first end of which is coupled to the second end of the third switch, and a second end of which is coupled to the ground; a fourth switch, a first terminal of which is coupled to the first terminal of the third capacitor; and A fourth capacitor has a first terminal coupled to the second terminal of the fourth switch and a second terminal coupled to the ground.

9. The drive control circuit according to claim 1, characterized in that: The control circuit comprises: A first comparison circuit, a first input terminal of which is coupled to the sampling signal, and a second input terminal of which is coupled to the first threshold; A second comparison circuit, a first input terminal of which is coupled to the second threshold, and a second input terminal of which is coupled to the sampling signal; and The OR gate has a first input terminal coupled to the output terminal of the first comparison circuit, a second input terminal coupled to the output terminal of the second comparison circuit, and an output terminal outputting an OR gate output signal.

10. The drive control circuit according to claim 9, characterized in that: The control circuit further comprises: The de-jitter time control circuit has its input terminals respectively coupled to the first comparison circuit and the second comparison circuit, and its output terminals respectively coupled to the OR gate, for preventing false triggering of the dynamic adjustment of the de-ripple loop bandwidth.

11. The drive control circuit according to claim 1, characterized in that: The control circuit is used to control the bandwidth of the ripple removal loop to recover to a steady-state value when no sampling signal is greater than a first threshold or less than a second threshold within n compensation voltage cycles, where n≥2.

12. An LED driving circuit, characterized in that: The LED driving circuit comprises the driving control circuit as described in any one of claims 1-11.

13. A drive control method for controlling a drive control circuit, characterized in that: The drive control method comprises: Acquire a sampling signal representing the compensation voltage, and acquire a sampling peak signal and a sampling valley signal within a preset period according to the sampling signal; Generate a first threshold and a second threshold according to the sampled peak signal and the sampled valley signal; in a steady state, the first threshold is greater than the sampled peak signal, and the second threshold is less than the sampled valley signal; and A loop bandwidth control signal is generated according to the sampling signal, the first threshold and the second threshold to adjust the de-ripple loop bandwidth; when the sampling signal is greater than the first threshold or less than the second threshold in one or several consecutive compensation voltage cycles, the de-ripple loop bandwidth is controlled to increase.

14. The driving control method according to claim 13, characterized in that: The step of generating the first threshold and the second threshold according to the sampled peak signal and the sampled valley signal includes: obtaining a sampled weighted signal according to the sampled peak signal and the sampled valley signal, generating the first threshold according to the sampled peak signal and the sampled weighted signal, and generating the second threshold according to the sampled valley signal and the sampled weighted signal.

15. The driving control method according to claim 14, characterized in that: The sampled weighted signal is a sampled average signal.

16. The driving control method according to claim 13, characterized in that: The step of generating the first threshold and the second threshold according to the sampled peak value signal and the sampled valley value signal comprises: Generate a sampled average signal according to the sampled peak value signal and the sampled valley value signal, and perform gain on the sampled average signal to generate a gain signal; The first filtered signal and the gain signal are added to obtain a first threshold; and the second filtered signal and the gain signal are subtracted to obtain a second threshold.

17. The driving control method according to claim 13, characterized in that: The drive control method further includes: When the sampling signal does not exceed the first threshold or is less than the second threshold within n compensation voltage cycles, the bandwidth of the ripple removal loop is controlled to recover to a steady-state value, n≥2.

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