CN204069427U - A kind of LED dimmer based on PAM and PWM - Google Patents
A kind of LED dimmer based on PAM and PWM Download PDFInfo
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- CN204069427U CN204069427U CN201420425600.8U CN201420425600U CN204069427U CN 204069427 U CN204069427 U CN 204069427U CN 201420425600 U CN201420425600 U CN 201420425600U CN 204069427 U CN204069427 U CN 204069427U
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Abstract
The utility model discloses a kind of LED dimmer based on PAM and PWM, comprise MCU, input rectifying filter circuit, power conversion circuit, output rectifier and filter and feedback control circuit.The invention also discloses a kind of light-dimming method of the LED dimmer based on PAM and PWM, comprise the following steps: 1, input rectifying filter circuit is to commercial power rectification filtering, then carry out power conversion via power conversion circuit; 2, described output rectifier and filter carries out rectifying and wave-filtering to waveform after power conversion; 3, the current sense resistor in described feedback control circuit and described output rectification filter forms feedback loop, realizes output constant current; 4, described MCU realize exporting the pulsewidth of impulse wave by control signal and amplitude adjustable.The utility model relates to LED light modulation field, has by keeping average current constant, when not changing LED luminance, by the duty ratio of regulating impulse electric current and the advantage of amplitude compensation look drift.
Description
Technical field
The utility model relates to a kind of LED light regulating technology, particularly a kind of LED dimmer based on PAM and PWM.
Background technology
LED, as lighting that is efficient, energy-saving and environmental protection, more and more replaces the traditional lighting light fixtures such as incandescent lamp.It is high that LED energy-conservation is embodied in luminous efficiency, and tunable optical.At present, the dimming mode of LED has two kinds: simulation light modulation and PWM light modulation.Simulation light modulation realizes light modulation by the forward conduction electric current changing LED, and PWM light modulation realizes light modulation by the impulse waveform that the certain duty ratio of adjusting amplitude is adjustable.Simulation light modulation owing to changing forward conduction size of current, look can be caused float, and PWM light modulation does not change amplitude, adjustment be pulse duration, therefore do not have look drift problem.
But along with the increase of LED lamp service time, the aging look that also can cause of fluorescent material floats, above-mentioned two kinds of light modulations cannot avoid look to float problem.Therefore the utility model proposes by producing pulse duration and the adjustable pulse current of amplitude, when aging generation look drift, by keeping average current constant, changing the amplitude driving LED of pulse current, can complementary color drift problem.
Utility model content
Primary and foremost purpose of the present utility model is that the shortcoming overcoming prior art is with not enough, provides a kind of LED dimmer based on PAM and PWM, and the look drift that this LED dimmer can realize causing because of problems such as LED are aging compensates.
Another object of the present utility model is that the shortcoming overcoming prior art is with not enough, a kind of light-dimming method being applied to LED dimmer based on PAM and PWM is provided, this light-dimming method when ensureing that average current is constant, by reducing duty ratio, can improve output current amplitude.
Primary and foremost purpose of the present utility model is achieved through the following technical solutions: a kind of LED dimmer based on PAM and PWM, comprise MCU, input rectifying filter circuit, power conversion circuit, output rectifier and filter and feedback control circuit, described input rectifying filter circuit is connected with described power conversion circuit, described power conversion circuit is connected with described feedback control circuit and described output rectifier and filter again, and described MCU is connected with described feedback control circuit and described output rectifier and filter, described MCU exports first via signal and the second road signal, described first via signal is reference signal, be input to the reference input of described feedback control circuit medial error amplifier, described second road signal is that pwm signal is for regulating the switching tube in described output rectifier and filter, ac input voltage rectifying and wave-filtering is level and smooth DC waveform by described input rectifying filter circuit, then deliver to described power conversion circuit, carry out power conversion via power conversion circuit and be delivered to described output rectifier and filter by the electronic transformer in described power conversion circuit, then carry out via described output rectifier and filter the level and smooth DC waveform that rectifying and wave-filtering obtains required voltage level, and then obtain impulse waveform by the switching tube copped wave in described output rectifier and filter, described feedback control circuit is made up of drive IC and error amplifier Amp and forms feedback loop with the current sense resistor in described output rectification filter, described feedback control circuit is sampled the output current in described output rectification filter, and together send into described error amplifier Amp two ends with the first via signal that described MCU exports, described drive IC is delivered to after amplifying via error amplifier Amp, described drive IC regulates the duty ratio of power switch pipe in described power conversion circuit, feedback loop realizes constant output current, meanwhile can by the amplitude regulating the first via signal of described MCU to carry out regulation output electric current, in addition, the duty ratio of regulation output current waveform can also be carried out by the duty ratio of the second road signal regulating described MCU.Therefore, this dimmer can realize exporting the pulsewidth of impulse wave by the uniting and adjustment of two switching tubes and amplitude all adjustable.
Described power conversion circuit comprises electronic transformer T, power switch pipe Q1, diode D1, electric capacity C1, resistance R1 and current sense resistor Rs1.
Described output rectifier and filter comprises diode D2, electric capacity C2, resistance R2, output capacitance Cout, switching tube Q2, current sense resistor Rs2, electric capacity C3 and voltage hold circuit.
Described feedback control circuit comprises drive IC and error amplifier Amp.
Described input rectifying filter circuit is connected with described power conversion circuit, and described power conversion circuit is connected with described feedback control circuit and described output rectifier and filter again, and described MCU is connected with described feedback control circuit and described output rectifier and filter, described MCU exports first via signal and the second road signal, described first via signal is reference signal, be input to the reference input of described feedback control circuit medial error amplifier, described second road signal is pwm signal, for regulating the switching tube in described output rectifier and filter, ac input voltage rectifying and wave-filtering is level and smooth DC waveform by described input rectifying filter circuit, then deliver to described power conversion circuit, carry out power conversion via power conversion circuit and be delivered to described output rectifier and filter by the electronic transformer in described power conversion circuit, then carry out via described output rectifier and filter the level and smooth DC waveform that rectifying and wave-filtering obtains required voltage level, and then obtain impulse waveform by the switching tube copped wave in described output rectifier and filter, described feedback control circuit is made up of drive IC and error amplifier Amp and forms feedback loop with the current sense resistor in described output rectification filter, described feedback control circuit is sampled the output current in described output rectification filter, and together send into described error amplifier Amp two ends with the first via signal that described MCU exports, described drive IC is delivered to after amplifying via error amplifier Amp, described drive IC regulates the duty ratio of power switch pipe in described power conversion circuit, feedback loop realizes constant output current, meanwhile can by the amplitude regulating the first via signal of described MCU to carry out regulation output electric current, in addition, the duty ratio of regulation output current waveform can also be carried out by the duty ratio of the second road signal regulating described MCU.
Therefore, the first via signal that above-mentioned LED dimmer can be produced by MCU and the second road signal realization regulate the amplitude of LED drive circuit output current and duty ratio, when ensureing that average current is constant, by reducing duty ratio, improve output current amplitude, realize the compensation of floating of checking colors.
Another object of the present utility model is achieved through the following technical solutions: a kind of light-dimming method being applied to LED dimmer based on PAM and PWM, comprises the steps:
Step one, mains input voltage obtains more level and smooth high voltage direct current through current rectifying and wave filtering circuit, then power conversion is carried out via power conversion circuit, power conversion circuit is by electronic transformer T, power switch pipe Q1, diode D1, electric capacity C1, resistance R1, current detecting Rs1 forms, when power switch pipe Q1 conducting, power conversion circuit forms closed-loop path, electric current flows through transformer T armature winding, electronic transformer T is flyback transformer, because the armature winding of electronic transformer T is contrary with secondary winding polarity, diode D2 reverse biased now in output rectifier and filter and ending, noenergy is sent to load, electric energy converts magnetic energy to and is stored in transformer, therefore in this step, power conversion circuit works, output rectifier and filter does not work, wherein, diode D1, electric capacity C1, resistance R1 form absorption circuit, for the peak voltage that transformer T leakage inductance in absorbed power switching tube Q1 turn off process produces.Current sense resistor Rs1 is for detecting transformer T primary inductance electric current.
Step 2, when in power conversion circuit, power switch pipe Q1 turns off, power conversion circuit does not work, transformer secondary output winding makes output rectifier and filter ON operation, the magnetic energy be stored in step one in transformer converts electric energy to and discharges in output rectifier and filter, transformer secondary output winding has electric current to flow through, and electric current reduces, to output capacitance Cout and load supplying, electric capacity C2, resistance R2 forms RC absorption circuit, the spike interference that RC absorption circuit produces for absorbing transformer, electric capacity C3 is used for filtering, voltage hold circuit keeps magnitude of voltage when opening constant for realizing current sense resistor Rs2 both end voltage in output rectifier and filter when switching tube turns off, do not lose efficacy when switching tube turns off to make feedback loop.
Step 3, feedback control circuit and current sense resistor Rs2 form feedback loop, controlled the duty ratio of the power switch pipe Q1 in power conversion circuit, realize constant output current by the electric current on current sense resistor Rs2.
Step 4, MCU export first via signal and the second road signal, and first via signal is reference signal, is input to the reference input of described feedback control circuit medial error amplifier, for the amplitude of regulation output constant current; Second road signal is that pwm signal is for regulating the duty ratio of the switching tube in described output rectifier and filter, output constant current is chopped off, realize pulse current to export, therefore, can adjustment second road signal dutyfactor regulation output pulse current waveform duty ratio be passed through.
By the coordination of above step, duty ratio and the amplitude that can realize output current are adjustable.
The utility model has following advantage and effect relative to prior art:
1, the first via signal that produced by MCU of LED dimmer of the present utility model and the second road signal realize regulating the amplitude of LED drive circuit output current and duty ratio, when ensureing that average current is constant, by reducing duty ratio, improve output current amplitude, realize the compensation of floating of checking colors.
2, the utility model can realize the duty ratio of output current and amplitude adjustable.
Accompanying drawing explanation
Fig. 1 is the block diagram of the better embodiment of a kind of LED dimmer based on PAM and PWM of the utility model.
Fig. 2 is the output current wave of a kind of LED dimmer based on PAM and PWM of the utility model.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the utility model is described in further detail, but execution mode of the present utility model is not limited thereto.
Embodiment
As shown in Figure 1, a kind of LED dimmer based on PAM and PWM comprises input rectifying filter circuit 1, power conversion circuit 2, output rectifier and filter 3, feedback control circuit 4 and MCU5.Mains input voltage obtains more level and smooth high voltage direct current through current rectifying and wave filtering circuit 1, then power conversion is carried out via power conversion circuit 2, power conversion circuit 2 is by electronic transformer T, power switch pipe Q1, diode D1, electric capacity C1, resistance R1, current detecting Rs1 forms, when power switch pipe Q1 conducting, power conversion circuit 2 forms closed-loop path, electric current flows through transformer T armature winding, electronic transformer T is flyback transformer, because the armature winding of electronic transformer T is contrary with secondary winding polarity, diode D2 reverse biased now in output rectifier and filter and ending, noenergy is sent to load, electric energy converts magnetic energy to and is stored in transformer, therefore in this step, power conversion circuit works, output rectifier and filter does not work, wherein, diode D1, electric capacity C1, resistance R1 form absorption circuit, and for the peak voltage that transformer T leakage inductance in absorbed power switching tube Q1 turn off process produces, current sense resistor Rs1 is for detecting transformer T primary inductance electric current.
When in power conversion circuit 2, power switch pipe Q1 turns off, transformer secondary loop and output rectifier and filter 3 conducting, the magnetic energy be stored in transformer converts electric energy release to, transformer secondary output winding has electric current to flow through, and electric current reduces, to output capacitance Cout and load supplying, electric capacity C2, resistance R2 forms RC absorption circuit, equally for absorbing the spike interference that transformer produces, electric capacity C3 is used for filtering, voltage hold circuit keeps magnitude of voltage when opening constant for realizing current sense resistor Rs2 both end voltage in output rectifier and filter when switching tube turns off, do not lose efficacy when switching tube turns off to make feedback loop.
Feedback control circuit 4 forms feedback loop with current sense resistor Rs2 in output rectifier and filter 3, is controlled the duty ratio of the power switch pipe Q1 in power conversion circuit 2, realize constant output current by the electric current on current sense resistor Rs2.
MCU5 exports first via signal and the second road signal, and first via signal is reference signal, is input to the reference input of the error amplifier in described feedback control circuit 4, for size or the amplitude of regulation output constant current; Second road signal is pwm signal, for regulating the duty ratio of the switching tube in described output rectifier and filter, output constant current being chopped off, realizing pulse current and exporting, therefore, adjustment second road signal dutyfactor regulation output pulse current waveform duty ratio can be passed through.
As shown in Figure 2, be output current wave figure, output current transforms to this conversion process of duty ratio D2 from duty ratio D1, and current amplitude keeps i1 constant, and duty ratio changes, and this adjustment process is that the second road signal by regulating MCU5 to export realizes.
Output current transforms to this conversion process of amplitude i2 from amplitude i1, and current duty cycle keeps D2 constant, and amplitude changes, and this adjustment process is that the first via signal by regulating MCU5 to export realizes.
In actual application, directly can skip second step, the first via signal exported by regulating MCU5 simultaneously and the second road signal, realize the adjustment of output current amplitude and duty ratio simultaneously.
Above-described embodiment is the utility model preferably execution mode; but execution mode of the present utility model is not restricted to the described embodiments; change, the modification done under other any does not deviate from Spirit Essence of the present utility model and principle, substitute, combine, simplify; all should be the substitute mode of equivalence, be included within protection range of the present utility model.
Claims (4)
1. the LED dimmer based on PAM and PWM, it is characterized in that, comprise MCU, input rectifying filter circuit, power conversion circuit, output rectifier and filter and feedback control circuit, described input rectifying filter circuit is connected with described power conversion circuit, described power conversion circuit is connected with described feedback control circuit and described output rectifier and filter respectively, and described MCU is connected with described feedback control circuit and described output rectifier and filter.
2. as required a kind of LED dimmer based on PAM and PWM as described in 1, it is characterized in that: described power conversion circuit comprises electronic transformer (T), power switch pipe (Q1), diode (D1), electric capacity (C1), resistance (R1) and current sense resistor (Rs1).
3. as required a kind of LED dimmer based on PAM and PWM as described in 1, it is characterized in that: described output rectifier and filter comprises diode (D2), electric capacity (C2), resistance (R2), output capacitance (Cout), switching tube (Q2), current sense resistor (Rs2), electric capacity (C3) and voltage hold circuit.
4. as required a kind of LED dimmer based on PAM and PWM as described in 1, it is characterized in that: described feedback control circuit comprises drive IC and error amplifier (Amp).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420425600.8U CN204069427U (en) | 2014-07-30 | 2014-07-30 | A kind of LED dimmer based on PAM and PWM |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420425600.8U CN204069427U (en) | 2014-07-30 | 2014-07-30 | A kind of LED dimmer based on PAM and PWM |
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| CN204069427U true CN204069427U (en) | 2014-12-31 |
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| CN201420425600.8U Expired - Fee Related CN204069427U (en) | 2014-07-30 | 2014-07-30 | A kind of LED dimmer based on PAM and PWM |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104159367A (en) * | 2014-07-30 | 2014-11-19 | 华南理工大学 | LED light modulator based on PAM and PWM and dimming method of LED light modulator based on PAM and PWM |
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2014
- 2014-07-30 CN CN201420425600.8U patent/CN204069427U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104159367A (en) * | 2014-07-30 | 2014-11-19 | 华南理工大学 | LED light modulator based on PAM and PWM and dimming method of LED light modulator based on PAM and PWM |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141231 Termination date: 20170730 |