CN203984727U - A kind of PWM light adjusting circuit for LED lamp - Google Patents
A kind of PWM light adjusting circuit for LED lamp Download PDFInfo
- Publication number
- CN203984727U CN203984727U CN201420310572.5U CN201420310572U CN203984727U CN 203984727 U CN203984727 U CN 203984727U CN 201420310572 U CN201420310572 U CN 201420310572U CN 203984727 U CN203984727 U CN 203984727U
- Authority
- CN
- China
- Prior art keywords
- circuit
- switch element
- constant
- light adjusting
- pwm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The utility model discloses a kind of PWM light adjusting circuit for LED lamp, comprise LED load, constant-current control circuit, pwm signal generator; Described pwm signal generator is connected with described constant-current control circuit; Described constant-current control circuit comprises switch element, is connected with one end of described LED load, controls the electric current of described LED load; When described pwm signal generator sends high level signal, described switch element conducting, described constant-current control circuit also comprises: feedback circuit, be connected between the base stage and emitter of described switch element, the pressure drop of described switch element is fed back to described switch element, the current constant that keeps described switch element, makes the current constant of described LED load.Adopt after technique scheme, can control more accurately the LED load current in PWM light adjusting circuit, thereby make the brightness adjustment of LED more accurate.
Description
Technical field
The utility model relates to illuminating lamp control circuit field, relates in particular to a kind of PWM light adjusting circuit for LED lamp.
Background technology
Consult Fig. 1, for the circuit diagram of the light adjusting circuit at present conventional LED lamp, in this circuit, driver control LED load current remains unchanged, by pwm signal generator, send pwm signal and control LED driver, thereby change the duty ratio of PWM and then the electric current of change LED.Therefore, the change by duty ratio makes LED electric current be linear transformation or is tending towards linear change.
But, although the control mode of this PWM light adjusting circuit is simple in prior art, easily to control, its light modulation precision is poor, and especially LED load is when low-light level, and its electric current has a large amount of ripples, affects the precision that electric current regulates.
To this, in some light adjusting circuits, also there is constant-current control circuit, concrete, utilize switch element to carry out current stabilization, but because switch element itself needs the electric current and the energy that consume, the effect that precision is improved is general.
Therefore, the utility model proposes the PWM light adjusting circuit that a kind of more high accuracy is controlled LED load current, improve further and utilize PWM to regulate duty recently to regulate the precision of LED load current.
Utility model content
The purpose of this utility model is to provide a kind of PWM light adjusting circuit for LED lamp, improves the control precision of constant-current circuit to LED load current, reduces the ripple of LED electric current.
The utility model discloses a kind of PWM light adjusting circuit for LED lamp, comprise LED load, constant-current control circuit, pwm signal generator; Described pwm signal generator is connected with described constant-current control circuit; Described constant-current control circuit comprises switch element, is connected with one end of described LED load, controls the electric current of described LED load; When described pwm signal generator sends high level signal, described switch element conducting, described constant-current control circuit also comprises: feedback circuit, be connected between the base stage and emitter of described switch element, the pressure drop of described switch element is fed back to described switch element, the current constant that keeps described switch element, makes the current constant of described LED load.
Preferably, described feedback circuit comprises load resistance R1 and comparator U1; Described load resistance R1 is connected between the emitter of described switch element and the reference edge of described comparator U1; The plus earth of described comparator U1, negative electrode is connected with the base stage of switch element.
Preferably, the base stage that reference edge and the negative electrode of described pressure drop by described comparator U1 feeds back to described switch element.
Preferably, described switch element comprises one of adjustment pipe Q1, triode, thyristor.
Preferably, when described switch element comprises adjustment pipe Q1, the base stage of described adjustment pipe Q1 is connected with described pwm signal generator, and the collector electrode of described adjustment pipe Q1 is connected with described LED load, the grounded emitter of described adjustment pipe Q1.
Preferably, described constant-current control circuit also comprises amplification driving circuit, is connected between described switch element and pwm signal generator.
Preferably, described amplification driving circuit comprises triode Q2; The base stage of described triode Q2 is connected with described pwm signal generator, and the collector electrode of described triode Q2 is connected with power supply, and the emitter of described triode Q2 is connected with the base stage of described switch element.
Preferably, described PWM light adjusting circuit also comprises constant-voltage control circuit, is connected with the collector electrode of described switch element.
Preferably, described constant-voltage control circuit comprises bleeder circuit, compensating circuit and regulating circuit; Described bleeder circuit is connected with the collector electrode of described switch element, and the voltage after output dividing potential drop is to described compensating circuit; Described compensating circuit regulates described voltage and exports described regulating circuit to; Described regulating circuit is controlled the duty ratio of the signal that described pwm signal generator sends.
Preferably, described bleeder circuit comprises resistance R 2 and the resistance R 3 of mutual series connection; Described compensating circuit comprises error amplifier; Described regulating circuit comprises an adjuster; The reverse input end of described error amplifier is in parallel with described resistance R 2 and resistance R 3; The output of described error amplifier and the positive input of described adjuster; The output of described adjuster is connected with described pwm signal generator.
Adopt after technique scheme, utilize feedback circuit that the pressure drop of switch element and loss Voltage Feedback are returned to switch element, the electric current of constant LED load, reduces the ripple in electric current, further improves the degree of regulation of PWM light adjusting circuit.
Accompanying drawing explanation
Fig. 1 is the circuit block diagram of PWM light adjusting circuit in prior art;
Fig. 2 is the circuit block diagram of PWM light adjusting circuit in the utility model one embodiment;
Fig. 3 is the circuit diagram of PWM light adjusting circuit in the utility model one embodiment;
Fig. 4 is the circuit diagram of constant voltage circuit in the utility model one embodiment.
Embodiment
Below in conjunction with accompanying drawing and specific embodiment, further set forth advantage of the present utility model.
Consulting Fig. 2, is the circuit block diagram of PWM light adjusting circuit in the utility model one embodiment.In this light adjusting circuit, it comprises LED load, constant-current control circuit and pwm signal generator.Wherein constant-current control circuit is connected between pwm signal generator and LED load, control to a certain extent the current constant of LED load, but its constant return as described above, not best, still leaves the space of further raising constant current effect.Constant-current control circuit has comprised switch element, and switch element can be that thyristor, triode etc. are by the electronic devices and components of circuit turn-on or disconnection.In one embodiment, switch element comprises adjusts pipe Q1, the base stage of adjusting pipe Q1 is connected with the output of pwm signal generator, makes the signal sending from pwm signal generator first through adjusting, to manage Q1, utilizes the linear operation mode of adjusting pipe Q1 to carry out accurate Limited Current amplitude.The collector electrode of adjusting pipe Q1 is connected with LED load, its grounded emitter, make the electric current of LED load be the size of current of the collector electrode of adjusting pipe Q1, if can guarantee, adjust the current constant of the collector electrode of managing Q1 and do not there is ripple, can guarantee that the electric current of LED load is accurately adjustable.In above-described embodiment, also can use other switch elements such as triode, thyristor to replace, but owing to adjusting pipe Q1 and have the pattern of linear work, its pressure drop is also by feedback circuit feedback canceller, therefore, is execution mode preferably.
The operation principle of PWM light adjusting circuit is: first pwm signal generator sends pwm signal to adjusting pipe Q1, adjusts pipe Q1 according to the conducting of low and high level state or the disconnection of pwm signal, wherein when send for high level time, adjust pipe Q1 conducting; When send when the low level, adjust pipe Q1 and disconnect.In this embodiment, constant-current control circuit has also comprised a feedback circuit, it is connected between the base stage and emitter of adjusting pipe Q1, owing to adjusting pipe Q1, generally all between its base stage and emitter, there is pressure drop, make to adjust pipe Q1 itself and consumed portion of energy, therefore, feedback circuit is connected between base stage and emitter, this pressure drop is fed back to and adjusts pipe Q1, the energy consuming is compensated the base stage of readjustment homogeneous tube Q1, utilize the pressure drop of adjusting pipe Q1 as feedback signal, when having limited the pressure drop of adjustment pipe Q1, eliminated the shortcoming of the high power consumption under linear model.And because the voltage of original loss is fed back to the base stage of adjusting pipe Q1, base voltage is constant, thereby the electric current that makes to export to from adjusting pipe Q1 LED load is steady state (its current value size is limited).Once the electric current of LED load is remained on to steady state, its working frequency ripple wave also will be eliminated.
Particularly, consulting Fig. 3, is the circuit diagram of PWM light adjusting circuit in the utility model one embodiment.In the preferred embodiment, feedback circuit includes load resistance R1 and comparator U1.Wherein, load resistance R1 is connected between the emitter of switch element and the reference edge of comparator U1, and the anode of comparator U1 is ground connection, and its negative electrode is connected with the base stage of switch element.Comparator U1 will compare the voltage of base stage and the voltage at reference edge emitter place thereof of negative electrode place switch element, and by disappearance voltage---pressure drop feeds back to the base stage that negative electrode is switch element, thereby reach, utilize the pressure drop of switch element as the technique effect of feedback signal.
In above-described embodiment, also can adopt other can play part or all by voltage, be recovered to input and base voltage and compare (be added or subtract each other), and with effective input signal of gained relatively, remove to control the feedback circuit of the voltage of emitter output, all may be implemented in the present embodiment, be not limited to the configuration of the above-mentioned use comparator U1 mentioning and load resistance R1.
Further, switch element or as being also provided with an amplification driving circuit between the adjustment pipe Q1 of switch element and pwm signal generator, the pwm signal that this amplification driving circuit sends pwm signal generator amplifies and voltage stabilizing, then driving switch element work.Consider that the pwm signal driving force that some pwm signal generator sends enough carrys out by force driving switch element, this amplification driving circuit is selectable, according to the requirement of side circuit, configures.
In one embodiment, amplification driving circuit can comprise triode Q2, and the base stage of triode Q2 is connected with pwm signal generator, and collector electrode is connected with power supply, and emitter is connected with the base stage of switch element, as the use of amplifying pwm signal.Certainly, it may occur to persons skilled in the art that, utilize the amplification driving circuits such as metal-oxide-semiconductor or amplifier tracking to replace the triode Q2 in the present embodiment can play same effect.
Continue to consult Fig. 3, in another preferred embodiment, PWM light adjusting circuit also includes constant voltage (CV) control circuit, is connected in the collector electrode of switch element, makes further the voltage of the collector electrode of switch element be pressure constant state.Wherein, consulting Fig. 4, is the circuit diagram of constant voltage in an embodiment (CV) control circuit, and constant-voltage control circuit includes bleeder circuit, compensating circuit and regulating circuit.Bleeder circuit is connected with the collector electrode of switch element, and by the Voltage-output after dividing potential drop to compensating circuit.Compensating circuit receives after voltage, effect through compensating parameter regulates this voltage and exports a magnitude of voltage to regulating circuit, the duty ratio of the signal that regulating circuit sends according to the magnitude of voltage control pwm signal generator receiving, thereby control output voltage and the electric current of collector electrode, when PWM duty ratio reduces, output voltage reduces, otherwise output voltage raises.Under stable state, be constant during output voltage.
More specifically, bleeder circuit comprises resistance R 2 and the resistance R 3 of mutual series connection, by resistance R 2 and R3, the voltage Vo of collector electrode is carried out to dividing potential drop.Compensating circuit includes an error amplifier (E/A), the positive input of error amplifier is connected with a reference power source Vref, reverse input end is connected to 3 of resistance R 2 and resistance R, in parallel with these two resistance respectively, its output is connected to the positive input of the adjuster in regulating circuit, and the output of adjuster is connected with pwm signal generator, the magnitude of voltage of adjuster output has determined the duty ratio of the output pwm signal of PWM generator, when the magnitude of voltage of the collector electrode of switch element is high, after dividing potential drop, this output voltage has surpassed Vref, regulator output voltage reduces, the magnitude of voltage of the positive input reception of adjuster is reduced, thereby output voltage reduces, PWM duty ratio reduces.
In this constant-voltage control circuit, what voltage Vo reacted is the collector electrode of the adjustment pipe Q1 in Fig. 3 and the voltage difference of emitter, and when pwm signal is duty ratio 100%, this voltage Vo is a relatively constant value, the collector voltage of Direct Sampling adjustment pipe Q1; And when pwm signal duty ratio is not 100%, adjusting the pipe collector electrode of Q1 and the voltage difference of emitter is a waveform that approaches square wave.When adjustment pipe Q1 opens, adjusting the pipe collector electrode of Q1 and the voltage difference of emitter is normal loss pressure drop; When adjusting pipe Q1 shutoff, adjust the output total voltage of the power supply that the pipe collector electrode of Q1 react with the voltage difference of emitter, voltage Vo is the collector electrode of adjustment pipe Q1 and the pressure drop of emitter (valley of the collector electrode of Q1 and the voltage of emitter is managed in namely adjustment) when adjusting pipe Q1 and opening.
By the configuration in above-described embodiment, when pwm signal generator output high level, triode Q2, adjust pipe Q1 conducting, the electric current of adjustment pipe Q1 is because the feedback effect of comparator U1 is steady state, and when pwm signal generator output low level, adjusting pipe Q1 electric current is 0; The operating state of adjusting pipe Q1 is copped wave state, and the electric current of LED is also the work of copped wave state, the current constant of the LED load under copped wave state and steadily ripple-free, thus reached the object of accurate light modulation.
Should be noted that, embodiment of the present utility model has preferably implementation, and not the utility model is done to any type of restriction, any person skilled in art of being familiar with may utilize the technology contents change of above-mentioned announcement or be modified to the effective embodiment being equal to, in every case do not depart from the content of technical solutions of the utility model, any modification or equivalent variations and the modification above embodiment done according to technical spirit of the present utility model, all still belong in the scope of technical solutions of the utility model.
Claims (10)
1. for a PWM light adjusting circuit for LED lamp, comprise LED load, constant-current control circuit, pwm signal generator;
Described pwm signal generator is connected with described constant-current control circuit;
Described constant-current control circuit comprises switch element, is connected with one end of described LED load, controls the electric current of described LED load;
When described pwm signal generator sends high level signal, described switch element conducting, is characterized in that: described constant-current control circuit also comprises:
Feedback circuit, is connected between the base stage and emitter of described switch element, and the pressure drop of described switch element is fed back to described switch element, keeps the current constant of described switch element, makes the current constant of described LED load.
2. PWM light adjusting circuit as claimed in claim 1, is characterized in that:
Described feedback circuit comprises load resistance R1 and comparator U1;
Described load resistance R1 is connected between the emitter of described switch element and the reference edge of described comparator U1;
The plus earth of described comparator U1, negative electrode is connected with the base stage of switch element.
3. PWM light adjusting circuit as claimed in claim 2, is characterized in that:
The base stage that reference edge and the negative electrode of described pressure drop by described comparator U1 feeds back to described switch element.
4. PWM light adjusting circuit as claimed in claim 1, is characterized in that:
Described switch element comprises adjusts one of pipe Q1, triode, thyristor.
5. PWM light adjusting circuit as claimed in claim 4, is characterized in that:
When described switch element comprises adjustment pipe Q1, the base stage of described adjustment pipe Q1 is connected with described pwm signal generator, and the collector electrode of described adjustment pipe Q1 is connected with described LED load, the grounded emitter of described adjustment pipe Q1.
6. PWM light adjusting circuit as claimed in claim 1, is characterized in that:
Described constant-current control circuit also comprises amplification driving circuit, is connected between described switch element and pwm signal generator.
7. PWM light adjusting circuit as claimed in claim 6, is characterized in that:
Described amplification driving circuit comprises triode Q2;
The base stage of described triode Q2 is connected with described pwm signal generator, and the collector electrode of described triode Q2 is connected with power supply, and the emitter of described triode Q2 is connected with the base stage of described switch element.
8. PWM light adjusting circuit as claimed in claim 1, is characterized in that:
Described PWM light adjusting circuit also comprises constant-voltage control circuit, is connected with the collector electrode of described switch element.
9. PWM light adjusting circuit as claimed in claim 8, is characterized in that:
Described constant-voltage control circuit comprises bleeder circuit, compensating circuit and regulating circuit;
Described bleeder circuit is connected with the collector electrode of described switch element, and the voltage after output dividing potential drop is to described compensating circuit;
Described compensating circuit regulates described voltage and exports described regulating circuit to;
Described regulating circuit is controlled the duty ratio of the signal that described pwm signal generator sends.
10. PWM light adjusting circuit as claimed in claim 9, is characterized in that:
Described bleeder circuit comprises resistance R 2 and the resistance R 3 of mutual series connection;
Described compensating circuit comprises error amplifier;
Described regulating circuit comprises an adjuster;
The reverse input end of described error amplifier is in parallel with described resistance R 2 and resistance R 3;
The output of described error amplifier and the positive input of described adjuster;
The output of described adjuster is connected with described pwm signal generator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420310572.5U CN203984727U (en) | 2014-06-12 | 2014-06-12 | A kind of PWM light adjusting circuit for LED lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420310572.5U CN203984727U (en) | 2014-06-12 | 2014-06-12 | A kind of PWM light adjusting circuit for LED lamp |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203984727U true CN203984727U (en) | 2014-12-03 |
Family
ID=51982142
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420310572.5U Expired - Fee Related CN203984727U (en) | 2014-06-12 | 2014-06-12 | A kind of PWM light adjusting circuit for LED lamp |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203984727U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104507233A (en) * | 2014-12-27 | 2015-04-08 | 欧普照明股份有限公司 | LED driving control circuit |
| WO2016184169A1 (en) * | 2015-05-19 | 2016-11-24 | 深圳创维－Rgb电子有限公司 | Multi-channel dual-mode digital control led driving circuit and led lamp |
| CN108712807A (en) * | 2018-08-03 | 2018-10-26 | 江西美的贵雅照明有限公司 | The driving circuit of light emitting diode |
-
2014
- 2014-06-12 CN CN201420310572.5U patent/CN203984727U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104507233A (en) * | 2014-12-27 | 2015-04-08 | 欧普照明股份有限公司 | LED driving control circuit |
| WO2016184169A1 (en) * | 2015-05-19 | 2016-11-24 | 深圳创维－Rgb电子有限公司 | Multi-channel dual-mode digital control led driving circuit and led lamp |
| US10143072B2 (en) | 2015-05-19 | 2018-11-27 | Shenzhen Skyworth-Rgb Electronic Co., Ltd | Multi-channel dual-mode digital control LED driving circuit and LED lamp |
| CN108712807A (en) * | 2018-08-03 | 2018-10-26 | 江西美的贵雅照明有限公司 | The driving circuit of light emitting diode |
| CN108712807B (en) * | 2018-08-03 | 2024-01-09 | 美智光电科技股份有限公司 | Driving circuit of light emitting diode |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9081401B2 (en) | Switching regulator and control circuit and control method thereof | |
| CN101917120B (en) | Device for controlling high precision peak inductive current of switch power supply | |
| CN102655706B (en) | Light emitting element driver, control circuit and control method thereof | |
| TWI484739B (en) | Active power factor correction circuit and related pfc controller | |
| TWI479780B (en) | Synchronous buck converter | |
| CN104300773A (en) | Simple self-adaptation dummy-load circuit | |
| TWI363946B (en) | Power supplies, power supply controllers, and power supply controlling methods | |
| US10492259B2 (en) | Dimmable LED driver and dimming method | |
| CN203984727U (en) | A kind of PWM light adjusting circuit for LED lamp | |
| CN103747561A (en) | Load adjusting compensation switch power supply | |
| CN102354242A (en) | Power control circuit | |
| CN102711331B (en) | LED drive power supply | |
| US7579813B2 (en) | Power regulator having a voltage regulator module and having a voltage buffer module to provide a constant voltage output | |
| CN103701341A (en) | Voltage following type depth negative feedback constant current source device | |
| CN112383220B (en) | Control circuit and switching converter using same | |
| CN102545696A (en) | Maximum power tracking device and method for photovoltaic battery | |
| CN204707309U (en) | A kind of light adjusting circuit based on PWM | |
| CN203884027U (en) | LED constant current driving circuit for multipath adaptive load | |
| US9893608B2 (en) | Power supply device | |
| TWI400592B (en) | Low dropout regulator | |
| CN105208706B (en) | A kind of PWM light adjusting circuit for LED light | |
| CN104853486A (en) | PWM-based light adjusting circuit | |
| CN103179715A (en) | Constant current drive circuit of large-power light-emitting diode (LED) | |
| CN104253955A (en) | Low-power-consumption constant current and stable voltage control circuit and television | |
| CN211792154U (en) | Backlight control circuit, television and intelligent panel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141203 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |