CN202524600U - Buck LED constant current drive control circuit - Google Patents
Buck LED constant current drive control circuit Download PDFInfo
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- CN202524600U CN202524600U CN2012200272708U CN201220027270U CN202524600U CN 202524600 U CN202524600 U CN 202524600U CN 2012200272708 U CN2012200272708 U CN 2012200272708U CN 201220027270 U CN201220027270 U CN 201220027270U CN 202524600 U CN202524600 U CN 202524600U
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Abstract
The utility model discloses a buck LED constant current drive control circuit, which is characterized by comprising a buck circuit, an LED load current and voltage detection and conversion circuit, a controlled constant current source and an LED load. The buck circuit, the LED load current and voltage detection and conversion circuit and the controlled constant current source form a closed loop. The current outputted by the controlled constant current source to the main control circuit control end of the buck circuit is controlled by the LED load current and voltage detection and conversion circuit, and the magnitude of the current outputted by the buck circuit to the LED load is controlled by the controlled constant current source and is proportional to the controlled constant current source. The current flowing through the LED load is made constant to the predetermined value by the closed loop. With the technical scheme of the utility model, an accurate constant LED current is unlikely to be affected by the LED itself and changed forward voltage due to the rising temperature, and good protection functions for LED load open circuit and short circuit are provided.
Description
Technical field
The utility model relates to the led drive circuit technical field, is a kind of step-down LED constant-current driving control circuit specifically.
Background technology
Existing buck is claimed BUCK the led drive circuit of topology again; By main control circuit unit controls load LED electric current; The LED size of current is directly proportional with the input current of its current detecting end, is provided with a current threshold in it, when current detecting end input current rises to when identical with this threshold values; Load LED is current controlled and stop to rise, and the input current of current detecting end is directly proportional with load LED voltage.Because the LED forward voltage is a negative temperature characteristic; Cause load LED voltage to reduce with the PN junction temperature rising of LED; Because load LED voltage reduces, this master control will increase the output of load LED electric current so that load LED voltage remains unchanged, and make this circuit can't accurately control the LED electric current; Outputing to the LED electric current rises and rises along with the LED temperature; Make the LED long-term work cause LED to damage easily or the shortening LED life-span at overload, the LED of load simultaneously voltage individual difference causes each product LED electric current to have than big difference, has a strong impact on bulk article key performance consistency.This circuit also can't provide effective protection for load LED open circuit and short circuit simultaneously, causes governor circuit or relevant components and parts to damage easily at load LED open circuit and short circuit.
Summary of the invention
The purpose of the utility model provides the influence that forward voltage that a kind of LED of flowing through electric current do not rise by LED itself or Yin Wendu changes; And have load LED open circuit and a short-circuit protection function; Prevent that LED from damaging, the step-down LED constant-current driving control circuit that prolongs the useful life of LED.
The purpose of the utility model realizes through following technical scheme.
A kind of step-down LED constant-current driving control circuit; It is characterized in that: said step-down LED constant-current driving control circuit comprises reduction voltage circuit, load LED current/voltage detection and translation circuit, controlled constant-current source and load LED; Said reduction voltage circuit, load LED current/voltage detection and translation circuit, controlled constant-current source are formed a closed loop; The current controlled of governor circuit control end that said controlled constant-current source outputs to reduction voltage circuit detects and translation circuit in load LED current/voltage; The size of current that reduction voltage circuit outputs to load LED is controlled by controlled constant-current source and proportional with it, and said closed loop makes the current constant that flows through load LED in predefined numerical value.
Said controlled constant-current source connects PNP triode and four resistance and photoelectrical coupler by circuit and constitutes; Photoelectrical coupler is made up of a light-emitting diode and a triode; Transistor base is controlled by light-emitting diode; Wherein the base stage of PNP triode is connected with the emitter of photoelectrical coupler, and the output current of said controlled constant-current source is controlled by input voltage, and the control reduction voltage circuit outputs to electric current and the voltage of load LED.
Said load LED current/voltage detects and is made up of load LED current/voltage detection and transform controller, current sampling resistor and the load LED that circuit is connected with translation circuit; Said load LED current/voltage detection and translation circuit carry out real-time sampling to electric current and the voltage of load LED, and sampled result and fiducial value are relatively outputed to controlled constant-current source.
The said set point that flows through load LED size of current is that load LED current/voltage detects and translation circuit internal reference voltage and sampling resistor ratio, and said closed-loop path makes the electric current that flows through load LED constant all the time.
Said reduction voltage circuit 1 is a step down switching regulator circuit; Be formed by connecting in direct-flow input end mouth, circuit master controller, counnter attack diode, fly-wheel diode, outputting inductance and output capacitance circuit; Wherein the circuit master controller is connected with the controlled constant-current source circuit; Counnter attack diode cathode end be connected with the outputting inductance circuit again after fly-wheel diode positive terminal circuit is connected, wherein counnter attack diode cathode end is connected with the circuit main controller circuit.
The utility model compared with prior art has following advantage:
1) through the said technical scheme of the utility model,, the LED working life is guaranteed for load LED provides drive current accurately;
2) realize simply faults such as open circuit or short circuit are taken place load LED, effective protection is provided LED and drive circuit;
3) load LED voltage compatibility is good, and the properties of product consistency of batch process is good, and particularly step-down LED constant-current driving control circuit has load LED open circuit or short error protection and fault eliminating auto restore facility.
Description of drawings
Fig. 1 is the circuit theory diagrams of the utility model step-down LED constant-current driving control circuit.
Embodiment
Below in conjunction with accompanying drawing the utility model step-down LED constant-current driving control circuit is further specified.
Like Fig. 1; The utility model step-down LED constant-current driving control circuit comprises three major parts; Be respectively buck circuit 1, the detection of load LED current/voltage and translation circuit 2 and controlled constant-current source 3; This three partial circuit is formed a closed loop; Wherein controlled constant-current source 3 the current controlled of governor circuit control end that output to reduction voltage circuit 1 detects and translation circuit 2 in load LED current/voltage, and the size of current that reduction voltage circuit 1 outputs to load LED11 is controlled by controlled constant-current source 3 and proportional with it, thereby the electric current and the set point that flow through load LED11 are consistent; The set point of its size of current is that load LED current/voltage detects the ratio with translation circuit 2 internal reference voltages and sampling resistor 10, and this closed-loop path makes that to flow through load LED11 electric current constant all the time.Load LED11 is that a kind of LED by some combines.
Wherein controlled constant-current source 3 is made up of with resistance 19, resistance 17, resistance 16, resistance 15, resistance 13 and photoelectrical coupler 14 the PNP triode 18 that circuit connects; Photoelectrical coupler 14 is made up of a light-emitting diode and a triode; Transistor base is controlled by light-emitting diode; Wherein the base stage of PNP triode 18 is connected with the emitter of photoelectrical coupler 14, and the output current of controlled constant-current source 3 is controlled by input voltage, and control reduction voltage circuit 1 outputs to electric current and the voltage of load LED11.
Load LED current/voltage detects to be made up of integrated circuit with electric current and voltage detecting function and relevant components and parts with translation circuit 2; Be to detect with transform controller 12, current sampling resistor 10 by the load LED current/voltage that circuit connects to constitute specifically with load LED11; Load LED current/voltage detects and electric current and the voltage of 2 couples of load LED11 of translation circuit carry out real-time sampling, and sampled result and fiducial value are relatively outputed to controlled constant-current source 3.
Civil power flows behind rectifying and wave-filtering from port 4 and injects, and reduction voltage circuit 1 provides power supply for load LED11; Load LED current/voltage detects and to carry out real-time sampling with translation circuit 2 couples of load LED11 electric current and voltage and detect and the transform controller 12 internal reference value driving controlled constant-current source 3 that relatively bears results with load LED current/voltage; Controlled constant-current source 3 outputs to circuit master controller 5 electric currents thereby controlled, and this current value decision-making circuit master controller 5 is output as load LED11 current value, and is directly proportional with load LED11 current value; When load LED11 curtage value detects with translation circuit 2 set points greater than load LED current/voltage; Load LED current/voltage detects with translation circuit 2 will drive controlled constant-current source 3; Make it output to circuit master controller 5 electric currents and reduce, load LED11 electric current is corresponding to be reduced in proportion thereby make; When load LED11 electric current detects with translation circuit 2 set points less than load LED current/voltage; Load LED current/voltage detects with translation circuit 2 will drive controlled constant-current source 3; Make it output to circuit master controller 5 electric currents and increase, thereby make corresponding the scaling up of load LED11 electric current; Above real-time closed-loop loop makes load LED11 electric current be constant at load LED current/voltage all the time and detects and translation circuit 2 set points.Short trouble appears in LED11 when load; When the detection of load LED current/voltage detects output current greater than the inner setting value with translation circuit 2; Load LED current/voltage detects with translation circuit 2 will drive controlled constant-current source 3; Make it output to that circuit master controller 5 electric currents reduce rapidly and near zero, thereby the output of turn-offing reduction voltage circuit 1 make the unlikely damage that is protected of relevant components and parts; When load LED11 short trouble obtains getting rid of, circuit automatically restores to state in proper working order.The utility model step-down LED constant-current driving control circuit, ability is constant LED electric current accurately, the influence that the forward voltage that not risen by LED itself or Yin Wendu changes, and have good LED load open circuit and short-circuit protection function.
Claims (5)
1. step-down LED constant-current driving control circuit; It is characterized in that: said step-down LED constant-current driving control circuit comprises that reduction voltage circuit (1), load LED current/voltage detect and translation circuit (2), controlled constant-current source (3) and load LED (11); Said reduction voltage circuit (1), load LED current/voltage detect with translation circuit (2), controlled constant-current source (3) forms a closed loop; The current controlled of governor circuit control end that said controlled constant-current source (3) outputs to reduction voltage circuit (1) detects and translation circuit (2) in load LED current/voltage; The size of current that reduction voltage circuit (1) outputs to load LED (11) is controlled by controlled constant-current source (3) and proportional with it, and said closed loop makes the current constant that flows through load LED (11) in predefined numerical value.
2. step-down LED constant-current drive circuit according to claim 1; It is characterized in that: said controlled constant-current source (3) connects PNP triode (18) by circuit and constitutes with resistance (19), resistance (17), resistance (16), resistance (15), resistance (13) and photoelectrical coupler (14); Photoelectrical coupler (14) is made up of a light-emitting diode and a triode; Transistor base is controlled by light-emitting diode; Wherein the base stage of PNP triode (18) is connected with the emitter of photoelectrical coupler (14), and the output current of said controlled constant-current source (3) is controlled by input voltage, and control reduction voltage circuit (1) outputs to electric current and the voltage of load LED (11).
3. step-down LED constant-current drive circuit according to claim 1; It is characterized in that: said load LED current/voltage detects the load LED current/voltage that is connected by circuit with translation circuit (2) and detects and transform controller (12), current sampling resistor (10) and load LED (11) formation; Said load LED current/voltage detection and translation circuit (2) carry out real-time sampling to electric current and the voltage of load LED (11), and sampled result and fiducial value are relatively outputed to controlled constant-current source (3).
4. step-down LED constant-current drive circuit according to claim 3; It is characterized in that: the said set point that flows through load LED (11) size of current is that load LED current/voltage detects and translation circuit (2) internal reference voltage and sampling resistor (10) ratio, and said closed-loop path makes the electric current that flows through load LED (11) constant all the time.
5. step-down LED constant-current drive circuit according to claim 1; It is characterized in that: said reduction voltage circuit (1) is a step down switching regulator circuit; Be formed by connecting in direct-flow input end mouth (4), circuit master controller (5), counnter attack diode (6), fly-wheel diode (7), outputting inductance (8) and output capacitance (9) circuit; Wherein circuit master controller (5) is connected with controlled constant-current source (3) circuit; Counnter attack diode (6) positive terminal be connected with outputting inductance (8) circuit again after fly-wheel diode (7) positive terminal circuit is connected, wherein counnter attack diode (6) negative pole end is connected with circuit master controller (5) circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012200272708U CN202524600U (en) | 2012-01-20 | 2012-01-20 | Buck LED constant current drive control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012200272708U CN202524600U (en) | 2012-01-20 | 2012-01-20 | Buck LED constant current drive control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202524600U true CN202524600U (en) | 2012-11-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012200272708U Expired - Fee Related CN202524600U (en) | 2012-01-20 | 2012-01-20 | Buck LED constant current drive control circuit |
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| Country | Link |
|---|---|
| CN (1) | CN202524600U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103079311A (en) * | 2012-12-27 | 2013-05-01 | 木林森股份有限公司 | Double loop controlled LED (Light Emitting Diode) driving circuit |
| CN103619110A (en) * | 2013-12-10 | 2014-03-05 | 惠州市华阳光电技术有限公司 | Circuit and method for improving resistance capacitance voltage-reducing constant current accuracy |
| CN105898952A (en) * | 2014-12-19 | 2016-08-24 | 毛昭祺 | Maximum output current setting circuit of LED driving power supply |
-
2012
- 2012-01-20 CN CN2012200272708U patent/CN202524600U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103079311A (en) * | 2012-12-27 | 2013-05-01 | 木林森股份有限公司 | Double loop controlled LED (Light Emitting Diode) driving circuit |
| CN103619110A (en) * | 2013-12-10 | 2014-03-05 | 惠州市华阳光电技术有限公司 | Circuit and method for improving resistance capacitance voltage-reducing constant current accuracy |
| CN103619110B (en) * | 2013-12-10 | 2016-04-06 | 惠州市华阳光电技术有限公司 | A kind of circuit and method improving resistance-capacitance depressurization constant current accuracy |
| CN105898952A (en) * | 2014-12-19 | 2016-08-24 | 毛昭祺 | Maximum output current setting circuit of LED driving power supply |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C53 | Correction of patent for invention or patent application | ||
| CB03 | Change of inventor or designer information |
Inventor after: Liang Jiandong Inventor after: Xiao Bin Inventor after: Zhang Hongwei Inventor after: Wang Zhenxing Inventor before: Shang Bin Inventor before: Zhang Hongwei Inventor before: Wang Zhenxing |
|
| COR | Change of bibliographic data |
Free format text: CORRECT: INVENTOR; FROM: SHANG BIN ZHANG HONGWEI WANG ZHENXING TO: LIANG JIANDONG XIAO BIN ZHANG HONGWEI WANG ZHENXING |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20121107 Termination date: 20140120 |