CN213073183U - PWM dimming control circuit without stroboscopic effect - Google Patents
PWM dimming control circuit without stroboscopic effect Download PDFInfo
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- CN213073183U CN213073183U CN202022333955.2U CN202022333955U CN213073183U CN 213073183 U CN213073183 U CN 213073183U CN 202022333955 U CN202022333955 U CN 202022333955U CN 213073183 U CN213073183 U CN 213073183U
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Abstract
The utility model discloses a there is not stroboscopic PWM dimming control circuit, produce module and switch unit including rectifier bridge, load, benchmark, still include PWM voltage conversion module, benchmark modulation module, integral loop control module and drive module. Wherein, the VR signal that the conversion of benchmark modulation module obtained is more level and smooth, is close to analog signal more to improve integral loop control module's sampling precision, integral loop control module's precision improves and makes drive module output more accurate control switch unit work's signal, effectively avoided the emergence of stroboscopic phenomenon. The utility model provides a pair of there is not stroboscopic PWM control circuit that adjusts luminance solves the PWM that prior art exists effectively and adjusts luminance the in-process stroboscopic serious for people's eye visual fatigue causes the problem of very big injury to causing people's eye, and the effect is showing, is suitable for extensive popularization.
Description
Technical Field
The utility model relates to a LED dimming control technical field, in particular to, a do not have stroboscopic PWM dimming control circuit.
Background
LED lighting is widely used for its advantages of high brightness, high efficiency, long life, etc. With the development of society, intelligent lighting is gradually popularized, and PWM (Pulse Width Modulation) dimming becomes a main control mode of intelligent dimming.
The traditional PWM dimming chip achieves the purpose of dimming by directly cutting the wave (as shown in fig. 1 to 5), and the PWM dimming is to connect an MOS switch tube in series with the LED load, and adjust the brightness of the LED load by adjusting the on-off duration of the MOS switch tube to change the on-off duration of the LED load. The PWM dimming control is simple and easy to realize, but the obvious defect of stroboflash exists due to the fact that the LED load is repeatedly switched on and off, and the stroboflash can cause eye visual fatigue, greatly injure eyes and influence visual health.
In view of this, it is desirable to provide a PWM control circuit that effectively solves the problems existing in the prior art that the strobe is severe during the PWM dimming process, so that human eyes are visually fatigued and the human eyes are greatly injured.
SUMMERY OF THE UTILITY MODEL
To the above defect, the utility model provides a technical problem lie in, provide a there is not stroboscopic PWM control circuit that adjusts luminance to solve the PWM that prior art exists and adjust luminance the in-process stroboscopic serious, make people's eye visual fatigue, to causing the problem of very big injury of people's eye.
The utility model provides a there is not stroboscopic PWM dimming control circuit includes rectifier bridge, load and switch unit, still includes PWM voltage conversion module, benchmark modulation module, integral loop control module and drive module, wherein, PWM voltage conversion module converts PWM _ OUT signal into the required PWM _ IN signal of chip; the reference modulation module is used for converting a reference signal V into a reference signalREFModulated to V with duty cycle IN accordance with the PWM _ IN signalRA PWM signal; the integral loop control module divides the VRPWM signal is converted into average DC signal V through integrationCOMP(ii) a The driving module is used for driving the sampling module to generate a sampling signal and an average direct current signal V according to the sampling signal and the average direct current signal VCOMPAnd controlling the on-off of the loop.
Preferably, a filter is further included, the filter converting the VRThe PWM signal is preliminarily simulated and converted into VRA signal to improve sampling accuracy of the integral loop control module.
Preferably, the PWM voltage conversion module comprises a first comparator based on a first referenceSignal VREF1Converting the PWM _ OUT signal to the PWM _ IN signal.
Preferably, the reference modulation module includes a first inverter, a second inverter, a first switching unit, and a second switching unit, wherein the first inverter controls an operation of the first switching unit according to the PWM _ IN signal; the second inverter controls the second switching unit to operate according to the PWM _ IN signal; the first switch unit controls the on-off of the filter and a power supply; and the second switch unit controls the on-off of the filter and the ground wire.
Preferably, the integration loop control module is an analog integrator or a digital integrator.
Preferably, the driving module comprises a second comparator according to the VCOMPThe signal and the load electric signal control the switch unit to work.
According to the above technical scheme, the utility model provides a pair of no stroboscopic PWM dimming control circuit compares with prior art, and the VR signal that its benchmark modulation module conversion obtained is more level and smooth, is close analog signal more to improve integral loop control module's sampling precision, integral loop control module's precision improves and makes the signal of more accurate control switch unit work of drive module output, effectively avoided stroboscopic phenomenon's emergence. The utility model discloses it is serious to solve the PWM that prior art exists effectively and adjust luminance in-process stroboscopic for people's eye visual fatigue causes the problem of very big injury to cause people's eye, and the effect is showing, is suitable for extensive popularization.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a block diagram of a conventional PWM dimming LED driving circuit;
fig. 2 is a first operating waveform diagram of the conventional PWM dimming LED driving circuit shown in fig. 1;
fig. 3 is a second operating waveform diagram of the conventional PWM dimming LED driving circuit shown in fig. 1;
fig. 4 is a third operating waveform diagram of the conventional PWM dimming LED driving circuit shown in fig. 1;
fig. 5 is a fourth waveform diagram illustrating the operation of the conventional PWM dimming LED driving circuit shown in fig. 1;
fig. 6 is a first block diagram of a PWM dimming control circuit without strobe according to an embodiment of the present invention;
fig. 7 is a block diagram of a PWM dimming control circuit without strobe according to an embodiment of the present invention;
fig. 8 is a first waveform diagram illustrating the operation of the PWM dimming control circuit without strobe shown in fig. 7;
fig. 9 is a second waveform diagram illustrating the operation of the PWM dimming control circuit without strobe shown in fig. 7;
fig. 10 is a third operating waveform diagram of the PWM dimming control circuit without strobe shown in fig. 7;
fig. 11 is a fourth waveform diagram illustrating the operation of the PWM dimming control circuit without strobe shown in fig. 7;
fig. 12 is a waveform diagram illustrating operation of the PWM dimming control circuit without strobe shown in fig. 7;
fig. 13 is a sixth waveform diagram illustrating the operation of the PWM dimming control circuit without strobe shown in fig. 7;
fig. 14 is a waveform diagram seven illustrating an operation of the PWM dimming control circuit without strobe shown in fig. 7.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 6, a specific embodiment of a PWM dimming control circuit without strobe according to the present invention will now be described. The stroboflash-free PWM dimming control circuit comprises a rectifier bridge, a load, a reference generation module, a switch unit, a PWM voltage conversion module, a reference modulation module, an integral loop control module and a driving module, wherein the PWM voltage conversion module converts a PWM _ OUT signal into a PWM _ IN signal required by a chip; the reference modulation module converts the reference signal VREFModulated to V with duty cycle coincident with PWM _ IN signalRA PWM signal; integral loop control module divides VRPWM signal is converted into average DC signal V through integrationCOMP(ii) a The driving module is used for driving the sampling module to generate a sampling signal and an average direct current signal VCOMPAnd controlling the on-off of the loop.
The reference generation module generates a reference signal VREFA reference signal VREFThe PWM _ IN signal obtained by the conversion of the PWM voltage conversion module is also transmitted to the reference modulation module, and the reference modulation module transmits the obtained reference signal VREFAnd PWM _ IN signal, outputting preliminarily simulated VRA PWM signal; vRThe PWM signal is converted by the integral loop control module to output an average direct current signal VCOMPThe drive module is according to VCOMPAnd a load electric signal VCSAnd the switch unit is controlled to work, so that PWM dimming of the LED is realized. The switch unit is an MOS tube, the current of the MOS source end is equal to the output current of the LED, so that the current of the LED is ILED＝ICS＝VCOMP/RCS＝D*VREF/RCSWherein R isCSReferring to fig. 8 to 14, it can be seen that the circuit structure not only realizes PWM dimming, but also eliminates the problem of stroboflash in PWM dimming.
Compared with the prior art, the VR signal that this kind of no stroboscopic PWM dimming control circuit's benchmark modulation module conversion obtained is more level and smooth, is close to analog signal more to improve integral loop control module's sampling precision, integral loop control module's precision improves and makes drive module output more accurate control switch unit work's signal, has effectively avoided the emergence of stroboscopic phenomenon. The non-stroboscopic PWM dimming control circuit effectively solves the problems that stroboscopic is serious in the PWM dimming process in the prior art, human eyes are visual fatigue, and the human eyes are greatly damaged.
IN this embodiment, the non-strobe PWM dimming control circuit further includes a filter, and the reference modulation module receives the PWM _ IN signal, and compares the reference V according to the duty ratio of the PWM _ IN signalREFModulating and outputting a modulation signal V with a duty ratio corresponding to the PWM signalRPWM, filter is to be VRThe PWM signal is preliminarily simulated and converted into VRThe filter is used for preliminarily simulating the PWM signals, so that the signals are smoother and closer to the analog signals, and the sampling precision of the integral loop control module is improved.
Referring to fig. 7, IN the present embodiment, the reference modulation module includes a first inverter, a second inverter, a first switching unit and a second switching unit, wherein the first inverter controls the first switching unit to operate according to the PWM _ IN signal; the second inverter controls the second switch unit to work according to the PWM _ IN signal; the first switch unit controls the on-off of the filter and the power supply; the second switch unit controls the on-off of the filter and the ground wire.
When the operational amplifier output of the PWM voltage conversion module is negative, the output signal is positive through the first inverter, the first inverter controls the second switch to be closed, the output signal is negative through the second inverter, the second inverter controls the first switch to be disconnected, and at the moment, the filter is discharged; when the operational amplifier output of the PWM voltage conversion module is positive, the output signal is negative through the first phase inverter, the first phase inverter controls the second switch to be switched off, the output signal is positive through the second phase inverter, the second phase inverter controls the first switch to be switched on, and at the moment, V isREFThe filter is charged.
In this embodiment, the integration loop control module is an analog integrator or a digital integrator. The positive input of the integral loop control module receives VRSignal, the negative input end obtains the electric signal of the output end, thereby forming aA negative feedback loop, the bandwidth of which is usually only a few Hz or ten-odd Hz, and the frequency of the PWM signal is usually 500 Hz-4K, so the output V of the integral loop control moduleCOMPIs VRA direct current signal of the average value of the signals, thereby forming a reference signal V which is in linear relation with the PWM duty ratioCOMPNamely: vCOMP＝D*VREFIn which V isREFIs the reference signal voltage. It is within the scope of the present disclosure that the above-described integral loop control module correlation performance function can be achieved.
In this embodiment, the PWM voltage conversion module includes a first comparator according to a first reference signal VREF1The PWM _ OUT signal is converted to a PWM _ IN signal. The driving module comprises a second comparator according to VCOMPThe signal and the load electric signal control the switch unit to work. The driver operates such that its positive terminal is equal to the negative terminal, ensuring VCOMP＝VCSIn which V isCSDriving the guarantee V for the feedback signal of the negative terminal of the switch unitCOMP＝VCSThe operational amplifier enables the positive end to be equal to the negative end, and the operational amplifier responds in real time. The LED load in the non-stroboscopic PWM dimming control circuit can be a single string of LEDs or a plurality of paths of LEDs, and various LED loads can realize the PWM dimming non-stroboscopic effect.
In this embodiment, the reference generating module includes a voltage converting unit, a bandgap reference unit, and a reference voltage unit, where the voltage converting unit takes power from the bus and converts the bus voltage into a working voltage; the band gap reference unit converts the working voltage into zero temperature coefficient voltage; the reference voltage unit acquires a preset reference value from the zero temperature coefficient voltage. Internal V of voltage conversion unitDDSupplying power to the band-gap reference unit to generate a reference voltage with zero temperature coefficient, inputting the reference voltage into the reference voltage unit to generate a reference signal, and superposing the PWM _ IN and the reference signal V output by the PWM voltage conversion module by the reference modulation moduleREFForm VRPWM. The analog signal is converted into approximate analog signal by filter to raise regulation precision and make it be in the bandwidth of integral loop control module, and the integral loop control module acts on the long-range average to make it be VCOMPAnd the LED dimming circuit is close to the PWM dimming circuit, so that the PWM dimming of the LED is realized without stroboflash.
Referring to fig. 6, a specific embodiment of a PWM dimming control method without strobe according to the present invention will now be described. According to the PWM dimming control method without stroboflash, an electric signal is obtained from a bus through a voltage module, the electric signal is processed into an electric signal with a zero temperature coefficient through a band gap reference module, and then a reference signal V is obtained through a reference moduleREFThe method comprises the following specific steps: the PWM _ OUT signal and a reference signal VREFAnd converting the signal into an analog signal to control the on-off of a loop.
The PWM _ OUT signal and a reference signal VREFConverting the signal into an analog signal, and controlling the on-off of a loop specifically comprises the following steps: converting the PWM _ OUT signal into a PWM _ IN signal required by the chip work through a PWM voltage conversion module; reference signal VREFModulated to V with duty cycle coincident with PWM _ IN signalRA PWM signal; vRThe PWM signal is converted into an analog signal V through the integral loop control moduleCOMPAnd as a reference value of the driving module, controlling the on-off of the loop, wherein the frequency of the PWM signal is greater than the frequency of the control module of the integral loop.
According to the PWM dimming control method without stroboflash, the PWM signal is converted into the analog signal, and the analog signal is used for controlling the on-off of the loop to realize dimming, so that the problem of stroboflash of PWM dimming can be well solved. The utility model discloses it is serious to solve the PWM that prior art exists effectively and adjust luminance in-process stroboscopic for people's eye visual fatigue causes the problem of very big injury to cause people's eye, and the effect is showing and is being suitable for extensive popularization.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. Details not described in the embodiments of the present invention belong to the prior art known to those skilled in the art.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. A PWM dimming control circuit without stroboflash comprises a rectifier bridge, a load and a switch unit, and is characterized by further comprising a PWM voltage conversion module, a reference modulation module, an integral loop control module and a driving module, wherein the PWM voltage conversion module converts a PWM _ OUT signal into a PWM _ IN signal required by a chip; the reference modulation module is used for converting a reference signal V into a reference signalREFModulated to V with duty cycle IN accordance with the PWM _ IN signalRA PWM signal; the integral loop control module divides the VRPWM signal is converted into average DC signal V through integrationCOMP(ii) a The driving module is used for driving the sampling module to generate a sampling signal and an average direct current signal V according to the sampling signal and the average direct current signal VCOMPAnd controlling the on-off of the loop.
2. The non-strobe PWM dimming control circuit of claim 1, further comprising a filter that filters the VRThe PWM signal is preliminarily simulated and converted into VRA signal to improve sampling accuracy of the integral loop control module.
3. The non-strobe PWM dimming control circuit of claim 2, wherein the PWM voltage conversion module comprises a first comparator according to a first reference signal VREF1Converting the PWM _ OUT signal to the PWM _ IN signal.
4. The PWM dimming control circuit according to claim 2, wherein the reference modulation module comprises a first inverter, a second inverter, a first switch unit and a second switch unit, wherein the first inverter controls the first switch unit according to the PWM _ IN signal; the second inverter controls the second switching unit to operate according to the PWM _ IN signal; the first switch unit controls the on-off of the filter and a power supply; and the second switch unit controls the on-off of the filter and the ground wire.
5. The non-strobe PWM dimming control circuit of claim 2, wherein the integrating loop control module is an analog integrator or a digital integrator.
6. The non-strobe PWM dimming control circuit of claim 2, wherein the driving module comprises a second comparator according to the VCOMPThe signal and the load electric signal control the switch unit to work.
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| CN202022333955.2U CN213073183U (en) | 2020-10-19 | 2020-10-19 | PWM dimming control circuit without stroboscopic effect |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112188674A (en) * | 2020-10-19 | 2021-01-05 | 美芯晟科技（北京）有限公司 | PWM dimming control method and circuit without stroboflash |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112188674A (en) * | 2020-10-19 | 2021-01-05 | 美芯晟科技（北京）有限公司 | PWM dimming control method and circuit without stroboflash |
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Address after: Room 01, 10 / F, block a, Tiangong building, No.30 Xueyuan Road, Haidian District, Beijing Patentee after: Meixinsheng Technology (Beijing) Co.,Ltd. Address before: Room 01, 10 / F, block a, Tiangong building, No.30 Xueyuan Road, Haidian District, Beijing Patentee before: MAXIC TECHNOLOGY (BEIJING) Co.,Ltd. |
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