CN212231774U - PWM (pulse-width modulation) dimming switch power supply circuit with constant voltage and constant current output functions - Google Patents
PWM (pulse-width modulation) dimming switch power supply circuit with constant voltage and constant current output functions Download PDFInfo
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- CN212231774U CN212231774U CN202022810659.7U CN202022810659U CN212231774U CN 212231774 U CN212231774 U CN 212231774U CN 202022810659 U CN202022810659 U CN 202022810659U CN 212231774 U CN212231774 U CN 212231774U
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- 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
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- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
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- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The utility model discloses a PWM light modulation switch power supply circuit with constant voltage and constant current output functions, which comprises a PWM light modulation control circuit, a light modulation circuit, an output voltage feedback circuit and a LED light source; the PWM dimming control circuit outputs a PWM dimming signal and is connected to the dimming circuit so as to control the magnitude of the output current of the dimming circuit; the output voltage feedback circuit detects the output voltage of the dimming circuit and outputs the detected voltage component back to the dimming circuit, so that the dimming circuit works in a constant voltage state when the dimming circuit is provided with a constant voltage LED light source. The PWM dimming switch power supply circuit with the constant voltage and constant current output functions can provide constant current for the constant current LED light source, can also provide constant voltage for the constant voltage LED light source, meets the constant current requirement of a client, and also meets the constant voltage requirement of the client. The LED switching power supply circuit has two advantages, is simple in structure and is a high-quality LED switching power supply circuit without stroboflash.
Description
Technical Field
The utility model belongs to the dimming circuit field, in particular to PWM switching power supply circuit that adjusts luminance with constant voltage and constant current output function.
Background
As the constant-current PWM dimming switch power supply IC which can be used for driving the LED light source by multi-path common-anode output on the market is mostly free of constant-voltage output function and cannot be provided with a constant-voltage LED light source. Therefore, a PWM dimming circuit having both a constant current function and a constant voltage function is required. Can meet the constant current and constant voltage requirements of customers at the same time.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model provides a PWM dimming switch power supply circuit with constant voltage and constant current output function, aim at solves the single problem of PWM dimming switch circuit application scope.
The utility model provides a technical scheme of above-mentioned technical problem does:
a PWM dimming switch power supply circuit with constant voltage and constant current output functions comprises a PWM dimming control circuit, a dimming circuit, an output voltage feedback circuit and an LED light source; the PWM dimming control circuit outputs a PWM dimming signal and is connected to the dimming circuit so as to control the magnitude of the output current of the dimming circuit; the output voltage feedback circuit detects the output voltage of the dimming circuit and outputs the detected voltage component back to the dimming circuit, so that the dimming circuit works in a constant voltage state when the dimming circuit is provided with a constant voltage LED light source.
The dimming circuit comprises a dimming switching power supply IC1, a resistor R1, a resistor R2, a resistor R3, a MOS tube Q1, an inductor L1 and a relay diode D1; the output voltage feedback circuit comprises a resistor R6, a resistor R8, a resistor R9, a reference chip IC2 and a triode Q2;
the resistor R8 and the resistor R9 are connected in series, and the resistor R8 and the resistor R9 are connected with the LED light source in parallel; the pin A and the pin R of the reference chip IC2 are respectively connected with two ends of the resistor R9, the pin K is connected with one end of the resistor R6, and the other end of the resistor R6 is connected with the base electrode of the triode Q2; the emitter of the triode Q2 is connected with the resistor R3 and the dimming switching power supply IC1, and the collector is connected with the power supply; the resistor R3 and the S pole of the MOS transistor Q1 are both connected with the resistor R2, and the resistor R2 and the dimming switch power supply IC1 are grounded; the dimming switch power supply IC1 is further connected with the PWM dimming control circuit, the G pole of the MOS tube Q1 and a power supply, and the resistor R1 is further connected between the dimming switch power supply IC1 and the power supply in series; the D pole of the MOS transistor Q1 is connected with the relay diode D1 and the inductor L1.
Preferably, a resistor R5 is connected between the base of the transistor Q2 and the power supply.
Preferably, the resistor R5 is 68 Ω.
Preferably, a capacitor C5 is connected to the K pin of the reference chip IC2, the capacitor C5 is connected to a resistor R7, and the resistor R7 is connected to the resistor R8 and the resistor R9.
Preferably, a capacitor C1 is connected to the dimming circuit; the inductor L1 is connected with a capacitor C2; the resistor R1 is connected with a capacitor C3; the collector of the triode Q2 is connected with a capacitor C4; the capacitor C1, the capacitor C3 and the capacitor C4 are all grounded; the capacitor C2 is connected with a power supply. Preferably, the power supply is typically 56V.
Preferably, the resistor R9 is 1.8k Ω, and the resistor R8 is 33k Ω.
The utility model discloses following beneficial effect has: compared with a common circuit, the constant current PWM dimming circuit has the advantages that a voltage feedback circuit is added, so that the constant current PWM dimming circuit has a constant voltage output function and a constant current output function. Therefore, the utility model discloses both can provide the constant current to constant current LED light source, do provide constant voltage to constant voltage LED light source, satisfying the demand of customer constant current, also satisfy the demand of customer constant voltage simultaneously. The LED switching power supply circuit has two advantages, is simple in structure and is a high-quality LED switching power supply circuit without stroboflash.
Drawings
Fig. 1 is a schematic structural view of the present invention;
wherein the accompanying drawings illustrate:
the LED light source control circuit comprises a PWM dimming control circuit 1, a dimming circuit 2, an output voltage feedback circuit 3 and an LED light source 4.
Detailed Description
The embodiments of the present invention will now be described with reference to fig. 1:
a PWM dimming switch power supply circuit with constant voltage and constant current output functions comprises a PWM dimming control circuit 1, a dimming circuit 2, an output voltage feedback circuit 3 and an LED light source 4; the PWM dimming control circuit 1 outputs a PWM dimming signal and is connected to the dimming circuit 2 to control the magnitude of the output current of the dimming circuit; the output voltage feedback circuit 3 detects the output voltage of the dimming circuit 2, and outputs the detected voltage component back to the dimming circuit 2, so that the dimming circuit operates in a constant voltage state when the LED light source is provided with a constant voltage.
The dimming circuit 2 comprises a dimming switching power supply IC1, a resistor R1, a resistor R2, a resistor R3, a MOS tube Q1, an inductor L1 and a relay diode D1; the output voltage feedback circuit 3 comprises a resistor R6, a resistor R8, a resistor R9, a reference chip IC2 and a triode Q2;
the resistor R8 and the resistor R9 are connected in series, and the resistor R8 and the resistor R9 are connected with the LED light source 4 in parallel; the pin A and the pin R of the reference chip IC2 are respectively connected with two ends of the resistor R9, the pin K is connected with one end of the resistor R6, and the other end of the resistor R6 is connected with the base electrode of the triode Q2; the emitter of the triode Q2 is connected with the resistor R3 and the dimming switching power supply IC1, and the collector is connected with the power supply; the resistor R3 and the S pole of the MOS transistor Q1 are both connected with the resistor R2, and the resistor R2 and the dimming switch power supply IC1 are grounded; the dimming switch power supply IC1 is further connected with the PWM dimming control circuit 1, the G pole of the MOS tube Q1 and a power supply, and the resistor R1 is further connected between the dimming switch power supply IC1 and the power supply in series; the D pole of the MOS transistor Q1 is connected with the relay diode D1 and the inductor L1.
The PWM dimming control circuit 1 outputs a PWM dimming signal to the dimming circuit 2 to control the brightness of the LED light source 4.
In the dimming circuit 2: the pin 1 of the dimming switch power supply IC1 is connected with the resistor R3 and the resistor R4, and the other end of the resistor R4 is connected with the collector of the triode Q2. The resistor R3 is connected between the dimming switch power supply IC1 and the resistor R2, the resistance value of the resistor R2 is set to set the magnitude of the constant current, and the resistor R3 is used for setting the feedback component of the connected output voltage to make the circuit constant in voltage. The output voltage feedback signal is sent by the triode Q2, and after being divided by the resistor R3 and the resistor R4, the output voltage feedback signal is input to pin 1 of the dimming switch power supply IC1 to control the dimming switch power supply IC to output a proper output current, so as to achieve the purpose of constant output voltage. The 2 feet of the dimming switch power supply IC1 are ground feet and are connected with an input ground. The 3 pins are power supply pins of the dimming switch power supply IC1, and the 3 pins are connected after the current is limited by a resistor R1 from the power supply to provide electric energy for the dimming switch power supply IC 1. The pin 5 is connected with the PWM dimming control circuit 1 and receives a PWM dimming signal. The pin 6 is connected with the pin G of the MOS tube Q1 and is used for controlling the switch of the MOS tube. The current passes through the LED light source 4, the inductor L1, the MOS transistor Q1 and the resistor R2 in sequence and then goes down. When the MOS tube is controlled to be closed, because the current of the inductor L1 can not change suddenly, the current flows back to the power supply through the relay diode D1 and continues to output current for the LED light source.
The resistor R8 and the resistor R9 are connected in series and are connected in parallel with the LED light source 4 for detecting the voltage on the LED light source 4. The divided voltage is inputted to the R pin of the reference chip IC2 through the resistor R8 and the resistor R9, and compared with the internal reference voltage, when the inputted voltage is higher than the reference voltage, the current flowing into the K pin of the reference chip IC2 increases, otherwise, the current decreases to generate a voltage feedback signal, and the voltage feedback signal is supplied to the base of the transistor Q2. The triode Q2 amplifies and outputs the received inverted output voltage feedback signal again in the inverted state to obtain a positive output voltage feedback signal, and outputs the positive output voltage feedback signal to the dimming switch power supply IC 1. The resistor R6 is the base input resistor of the transistor Q2 and is used to set the magnitude of the voltage feedback signal input component. The resistance values of the resistor R8 and the resistor R9 are used for setting the constant voltage value of the circuit, and the formula is as follows: vout=VRR9 × (R8+ R9). Wherein, VoutIs the circuit voltage, VRIn general, the standard of the reference voltage of the R pin of the reference chip IC2 is 2.5V, which is the reference voltage of the R pin of the reference chip IC 2. The constant voltage state of the circuit is as follows: when the output is connected with the constant voltage LED light source, the PWM dimming is performed for 100 percent of output, and the output current is lower than the constant current value, the output voltage is not pulled down by the LED light source 4, and the output voltageAnd maintaining the constant voltage value to be in a constant voltage output state. At this time, the output voltage feedback circuit 3 has an output voltage feedback signal to the dimming circuit 2, and raises the voltage of pin 1 of the dimming switching power supply IC1, so as to reduce the output current by a proper amount, thereby achieving the effect of constant voltage output. Preferably, the power supply is typically 56V.
The circuit is in a constant current state: when the output is connected with the constant-current LED light source, the PWM dimming is performed for 100% output, the output current reaches the constant-current value, the output voltage is pulled down by the LED light source 4 and is lower than the constant-voltage value, and the circuit is in a constant-current state. The output voltage feedback circuit outputs no voltage feedback signal, and only the current output by the resistor R2 for current detection is fed back to pin 1 of the dimmer switch power supply IC 1. The circuit is in a state of outputting a constant current. In addition, the output current can be adjusted by adjusting the PWM dimming signal, so that the brightness of the light source is adjusted, and the purpose of constant-current dimming is achieved.
In one embodiment, a resistor R5 is connected between the base of the transistor Q2 and the power supply.
In one embodiment, the resistor R5 has a resistance of 68 Ω.
The resistor R5 is also connected in series with the K pin of the reference chip IC2, the minimum operating current of the reference chip IC2 is 1mA, and the resistor R5 is required to bypass the transistor Q2, so that the 1mA current does not flow through the emitter junction of the transistor Q2, that is, R5 × 1mA is 680 Ω × 1mA, 0.68V is less than 0.7V, the on-state voltage of the emitter junction is increased, the input threshold is increased, and the influence of the reference chip operating current on the transistor Q2 is eliminated.
In one embodiment, a capacitor C5 is connected to the K pin of the reference chip IC2, the capacitor C5 is connected to a resistor R7, and the resistor R7 is connected to the resistor R8 and the resistor R9.
The capacitor C5 and the resistor R7 are an alternating current negative feedback branch of the reference chip IC2, so that the working stability of the reference chip IC2 is improved, and the output voltage feedback signal waveform of a K pin is improved.
In one embodiment, the dimming circuit 2 is connected with a capacitor C1; the inductor L1 is connected with a capacitor C2; the resistor R1 is connected with a capacitor C3; the collector of the triode Q2 is connected with a capacitor C4; the capacitor C1, the capacitor C3 and the capacitor C4 are all grounded; the capacitor C2 is connected with a power supply.
The capacitor C1 is a filter capacitor of the circuit power supply, filters noise waves generated by the circuit or noise waves coming from the outside, and improves the stability of the circuit. The capacitor C2 is an output filter capacitor of the dimming circuit 2, and is used for filtering output noise waves and stabilizing output voltage and current. The capacitor C3 is a filter capacitor of the dimming switch power supply IC1, so that the power supply of the dimming switch power supply IC1 is cleaner and more stable. The voltage feedback signal output by the triode Q2 is filtered by the capacitor C4 to remove high-frequency noise, and then output to pin 1 of the dimming switching power supply IC 1.
In one embodiment, the resistor R9 has a resistance of 1.8k Ω, and the resistor R8 has a resistance of 33k Ω.
The reference voltage of the pin R of the reference chip IC2 is 2.5V, and the constant voltage value of the circuit is approximately 48.3V through the calculation of the formula, so that the LED light source is suitable for 48V LED light sources.
The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.
Claims (6)
1. A PWM dimming switch power supply circuit with constant voltage and constant current output functions is characterized by comprising a PWM dimming control circuit, a dimming circuit, an output voltage feedback circuit and an LED light source; the PWM dimming control circuit outputs a PWM dimming signal and is connected to the dimming circuit so as to control the magnitude of the output current of the dimming circuit; the output voltage feedback circuit detects the output voltage of the dimming circuit and outputs the detected voltage component back to the dimming circuit, so that the dimming circuit works in a constant voltage state when the dimming circuit is provided with a constant voltage LED light source;
the dimming circuit comprises a dimming switching power supply IC1, a resistor R1, a resistor R2, a resistor R3, a MOS tube Q1, an inductor L1 and a relay diode D1; the output voltage feedback circuit comprises a resistor R6, a resistor R8, a resistor R9, a reference chip IC2 and a triode Q2;
the resistor R8 and the resistor R9 are connected in series, and the resistor R8 and the resistor R9 are connected with the LED light source in parallel; the pin A and the pin R of the reference chip IC2 are respectively connected with two ends of the resistor R9, the pin K is connected with one end of the resistor R6, and the other end of the resistor R6 is connected with the base electrode of the triode Q2; the emitter of the triode Q2 is connected with the resistor R3 and the dimming switching power supply IC1, and the collector is connected with the power supply; the resistor R3 and the S pole of the MOS transistor Q1 are both connected with the resistor R2, and the resistor R2 and the dimming switch power supply IC1 are grounded; the dimming switch power supply IC1 is further connected with the PWM dimming control circuit, the G pole of the MOS tube Q1 and a power supply, and the resistor R1 is further connected between the dimming switch power supply IC1 and the power supply in series; the D pole of the MOS transistor Q1 is connected with the relay diode D1 and the inductor L1.
2. The power supply circuit of claim 1, wherein a resistor R5 is connected between the base of the transistor Q2 and the power supply.
3. A PWM dimming switching power supply circuit with constant voltage and constant current output function according to claim 2, wherein the resistor R5 has a resistance of 68 Ω.
4. A PWM dimming switching power supply circuit with constant voltage and constant current output function as claimed in claim 1, wherein the K pin of the reference chip IC2 is connected with a capacitor C5, the capacitor C5 is connected with a resistor R7, and the resistor R7 is connected with the resistor R8 and the resistor R9.
5. A PWM dimming switching power supply circuit having constant voltage and constant current output function according to claim 1, wherein a capacitor C1 is connected to the dimming circuit; the inductor L1 is connected with a capacitor C2; the resistor R1 is connected with a capacitor C3; the collector of the triode Q2 is connected with a capacitor C4; the capacitor C1, the capacitor C3 and the capacitor C4 are all grounded; the capacitor C2 is connected with a power supply.
6. A PWM dimming switching power supply circuit with constant voltage and constant current output function as claimed in claim 1, wherein the resistance R9 is 1.8k Ω, and the resistance R8 is 33k Ω.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022810659.7U CN212231774U (en) | 2020-11-30 | 2020-11-30 | PWM (pulse-width modulation) dimming switch power supply circuit with constant voltage and constant current output functions |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022810659.7U CN212231774U (en) | 2020-11-30 | 2020-11-30 | PWM (pulse-width modulation) dimming switch power supply circuit with constant voltage and constant current output functions |
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| CN212231774U true CN212231774U (en) | 2020-12-25 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116685014A (en) * | 2023-08-04 | 2023-09-01 | 无锡安特源科技股份有限公司 | Dimming control circuit and electronic equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116685014A (en) * | 2023-08-04 | 2023-09-01 | 无锡安特源科技股份有限公司 | Dimming control circuit and electronic equipment |
| CN116685014B (en) * | 2023-08-04 | 2023-10-20 | 无锡安特源科技股份有限公司 | Dimming control circuit and electronic equipment |
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