CN202095159U - Constant current driving circuit - Google Patents
Constant current driving circuit Download PDFInfo
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- CN202095159U CN202095159U CN2011202725799U CN201120272579U CN202095159U CN 202095159 U CN202095159 U CN 202095159U CN 2011202725799 U CN2011202725799 U CN 2011202725799U CN 201120272579 U CN201120272579 U CN 201120272579U CN 202095159 U CN202095159 U CN 202095159U
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Abstract
The utility model discloses a constant current driving circuit, which is used for outputting constant current to supply loads. The constant current driving circuit comprises a power supply for providing stable voltage, a current detection circuit, an amplifier circuit for amplifying voltage difference of two ends of the current detection circuit, a comparator and a steady current circuit, wherein a first input end of the comparator is connected with the output end of the amplifier circuit, a second input end of the comparator is connected with reference voltage, two ends of the steady current circuit are connected with the power supply and the current detection circuit, and a control end of the steady current circuit is connected with the output end of the comparator. By comparing the voltage of the two ends of the current detection circuit and the reference voltage, an obtained output signal controls the current of the steady current circuit. The circuit input and output are in the same return circuit so that the input current equals to the output current and a purpose that the input current and the output current are constant current.
Description
Technical field
The utility model relates to constant current technology, is specifically related to a kind of constant-current drive circuit.
Background technology
Constant current technology has obtained using widely at present, generally is output as constant current, for example for driving LED lamp group, just needs constant-current source.The New Times of lighting technology revolution has been opened up in the development of LED technology, makes the application technology also and then develop rapidly of LED illuminated area to automobile.The automobile LED light fixture adopts led light source, and it is strong to have illumination, and color rendering is good, and light is soft, the luminous efficiency height, and volume is little, and the life-span is long, firm characteristics such as reliably and non-thermal radiation, no poisonous metal mercury, environmental protection, and have multiple colour temperature available.
DC/DC LED power supply is development in nearly 2 a years high frequency switch power comparatively rapidly, and its trend is low-voltage, big electric current, low clearance, high power density and high efficiency or the like.The power density of product is more and more high, and output current is more and more big, and output voltage is more and more flexible, and product technology is more and more difficult.It is mainly used in automotive lighting, exhibition room, decoration, commerce, office, hotel, school and decorative lighting.Because the led drive circuit major part is to export the constant-current type control circuit at present, when changing for reaching power supply input 9-16V, the requirement of input current variable quantity △ Iin＜100mA needs to solve the problem of importing also constant current when exporting constant current.
General circuit is output 5 LEDs 3.0-3.3V series connection, output voltage 15-16.5V, than input voltage height, for realizing the input constant current, the electric current branch that has more in the time of input voltage 9-16V need being changed falls, insert the voltage-stabiliser tube shunt circuit at input and can realize this requirement, use foregoing circuit can solve the problem of input current △ Iin＜100mA under the normal temperature, but because voltage-stabiliser tube has negative temperature characterisitic, when in the range of temperature of-40 ~ 125 degree, working, the variable quantity of input current had been difficult to guarantee in △ Iin＜100mA scope actual measurement △ Iin when particularly-40 degree was spent with 125〉300mA.And the problem of temperature rise especially severe of voltage stabilizing didoe and current-limiting resistance, long-term work diode and current-limiting resistance might burn and cause circuit malfunction.
The utility model content
The utility model is an input current problem of unstable when being output as constant current during solution has now, thereby provides a kind of input and output to be the constant-current drive circuit of constant current.
For solving the problems of the technologies described above, the utility model provides following technical scheme:
A kind of constant-current drive circuit is used to export the constant current supply load, comprising: the power supply that burning voltage is provided; Galvanometer circuit; Be used for amplifier circuit with the voltage difference amplification at galvanometer circuit two ends; Comparator, the first input end of described comparator connects the output of amplifier circuit, and second input of comparator connects reference voltage; Current stabilization circuit, the two ends of described current stabilization circuit connect power supply and galvanometer circuit, and the control end of current stabilization circuit connects the output of described comparator.
Preferably, described galvanometer circuit is a resistance.
Preferably, described current stabilization circuit is the PNP transistor; The first input end of described comparator is a positive input terminal, and second input is a negative input end.
Preferably, described current stabilization circuit is a NPN transistor; The first input end of described comparator is a negative input end, and second input is a positive input terminal.
Further, described amplifier circuit comprises: operational amplifier, resistance R 3, resistance R 4, resistance R 5 and resistance R 6, the positive input terminal of described resistance R 4 concatenation operation amplifiers, the negative input end of resistance R 3 concatenation operation amplifiers, the negative input end of operational amplifier is connected with earth signal by resistance R 5, and the two ends of resistance R 6 are the positive input terminal and the output of concatenation operation amplifier respectively.
Preferably, described load is a LED lamp group.
Compared with prior art, the utlity model has following beneficial effect: a kind of constant-current drive circuit that the utility model provides, the size that compares galvanometer circuit both end voltage and reference voltage by comparator, the size of current of the output signal control current stabilization circuit that obtains, these circuit input and output are same loops, so input current and output current equate, have realized the purpose of input and output constant currents.
Description of drawings
Fig. 1 is the theory diagram of the utility model embodiment constant-current drive circuit.
Fig. 2 is the schematic diagram of the utility model first embodiment constant-current drive circuit.
Fig. 3 is the schematic diagram of the utility model second embodiment constant-current drive circuit.
Embodiment
Clearer for technical problem, technical scheme and beneficial effect that the utility model is solved, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explanation the utility model, and be not used in qualification the utility model.
Fig. 1 is the theory diagram of the utility model embodiment constant-current drive circuit; A kind of constant-current drive circuit is provided, has been used to export the constant current supply load, having comprised: the power supply 1 that burning voltage is provided; Galvanometer circuit 3; Be used for amplifier circuit 4 with the voltage difference amplification at galvanometer circuit two ends; Comparator U2, the first input end of described comparator U2 connects the output of amplifier circuit 4, and second input of comparator U2 connects reference voltage VREF; Current stabilization circuit 5, the two ends of described current stabilization circuit 5 connect power supply 1 and galvanometer circuit 3, and the control end of current stabilization circuit 5 connects the output of described comparator U2.The size that compares galvanometer circuit 3 both end voltage and reference voltage VREF by comparator U2, the size of current of the output signal control current stabilization circuit 5 that obtains, these circuit input and output are same loops, so input current and output current are equal, have realized the purpose of input and output constant currents.
Fig. 2 is the schematic diagram of the utility model first embodiment constant-current drive circuit; In the present embodiment, galvanometer circuit is a resistance R 1; Current stabilization circuit is the PNP transistor; The first input end of described comparator U2 is a positive input terminal, and second input is a negative input end; Amplifier circuit 4 comprises: operational amplifier U1, resistance R 3, resistance R 4, resistance R 5 and resistance R 6, the positive input terminal of described resistance R 4 concatenation operation amplifier U1, the negative input end of resistance R 3 concatenation operation amplifier U1, the negative input end of operational amplifier U1 is connected with earth signal by resistance R 5, and the two ends of resistance R 6 are positive input terminal and the output of concatenation operation amplifier U1 respectively.Load in the present embodiment is a LED lamp group; Load also can be other load elements that need constant current in other embodiments.
Be 12V with the supply voltage in the present embodiment, reference voltage VREF is 6.48V, and it is the example explanation that the operating voltage of operational amplifier U1 and comparator U2 is 24V:
When power supply 1 begins to work on power, the electric current that flows through R1 becomes big gradually, operational amplifier U1 detects the pressure drop of resistance R 1 and this pressure drop signal is amplified, and the multiplication factor of the amplifier circuit in the present embodiment is: (the * VR1 of R5 (R4+R6)/(R3+R5) R4+R6/R4); VR1 is the voltage on the resistance R 1.Amplifying signal output to comparator U2 end in the same way and and reference voltage VREF relatively, the signal of relatively output is exported to the transistorized base stage of PNP, control the electric current of PNP emitter thus, the control of realization constant current; If the pressure drop at resistance R 1 two ends is through amplifying the back greater than reference voltage VREF, comparator U2 exports high level, and the transistorized base stage of high level control PNP of output makes PNP transistor base voltage raise, thereby the electric current that flows through PNP emitter-collector electrode reduces, and then carries out current stabilization; Because input and output are same loops,, can guarantee input current variable quantity △ Iin＜100mA again, realize the purpose of input and output constant currents so input current and output current are equal.
Fig. 3 is the schematic diagram of the utility model second embodiment constant-current drive circuit; What the embodiment of this figure was different with embodiment among Fig. 2 is that current stabilization circuit 5 is a NPN transistor; The first input end of described comparator U2 is a negative input end, and second input is a positive input terminal.Because the signal of amplifier circuit 4 outputs is connected to the negative input end of comparator U2, reference voltage VREF is connected to the positive input terminal of comparator U2, if the pressure drop at resistance R 1 two ends is through amplifying the back greater than reference voltage VREF, comparator U2 output low level, the base stage of the low level control NPN transistor of output, make the NPN transistor base voltage reduce, thereby the electric current that flows through NPN transistor emitter-collector electrode reduces, and then carry out current stabilization; Because input and output are same loops,, can guarantee input current variable quantity △ Iin＜100mA again, realize the purpose of input and output constant currents so input current and output current are equal.
The above only is preferred embodiment of the present utility model; not in order to restriction the utility model; all any modifications of within spirit of the present utility model and principle, being done, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.
Claims (8)
1. a constant-current drive circuit is used to export the constant current supply load, it is characterized in that, comprising:
The power supply of burning voltage is provided;
Galvanometer circuit;
Be used for amplifier circuit with the voltage difference amplification at galvanometer circuit two ends;
Comparator, the first input end of described comparator connects the output of amplifier circuit, and second input of comparator connects reference voltage;
Current stabilization circuit, the two ends of described current stabilization circuit connect power supply and galvanometer circuit, and the control end of current stabilization circuit connects the output of described comparator.
2. constant-current drive circuit according to claim 1 is characterized in that, described galvanometer circuit is a resistance.
3. constant-current drive circuit according to claim 1 is characterized in that, described current stabilization circuit is the PNP transistor.
4. constant-current drive circuit according to claim 3 is characterized in that, the first input end of described comparator is a positive input terminal, and second input is a negative input end.
5. constant-current drive circuit according to claim 1 is characterized in that, described current stabilization circuit is a NPN transistor.
6. constant-current drive circuit according to claim 5 is characterized in that, the first input end of described comparator is a negative input end, and second input is a positive input terminal.
7. constant-current drive circuit according to claim 1, it is characterized in that, described amplifier circuit comprises: operational amplifier, resistance R 3, resistance R 4, resistance R 5 and resistance R 6, the positive input terminal of described resistance R 4 concatenation operation amplifiers, the negative input end of resistance R 3 concatenation operation amplifiers, the negative input end of operational amplifier is connected with earth signal by resistance R 5, and the two ends of resistance R 6 are the positive input terminal and the output of concatenation operation amplifier respectively.
8. according to each described constant-current drive circuit of claim 1 to 7, it is characterized in that described load is a LED lamp group.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202725799U CN202095159U (en) | 2011-07-29 | 2011-07-29 | Constant current driving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202725799U CN202095159U (en) | 2011-07-29 | 2011-07-29 | Constant current driving circuit |
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| Publication Number | Publication Date |
|---|---|
| CN202095159U true CN202095159U (en) | 2011-12-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011202725799U Expired - Fee Related CN202095159U (en) | 2011-07-29 | 2011-07-29 | Constant current driving circuit |
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| CN (1) | CN202095159U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103675419A (en) * | 2012-09-19 | 2014-03-26 | 深圳市海洋王照明工程有限公司 | Constant-current comparison circuit and LED lamp group current monitoring device |
| CN104602393A (en) * | 2013-10-31 | 2015-05-06 | 三星电机株式会社 | Light emitting diode driver |
-
2011
- 2011-07-29 CN CN2011202725799U patent/CN202095159U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103675419A (en) * | 2012-09-19 | 2014-03-26 | 深圳市海洋王照明工程有限公司 | Constant-current comparison circuit and LED lamp group current monitoring device |
| CN103675419B (en) * | 2012-09-19 | 2018-02-06 | 深圳市海洋王照明工程有限公司 | Constant current comparison circuit and LED light group current monitoring device |
| CN104602393A (en) * | 2013-10-31 | 2015-05-06 | 三星电机株式会社 | Light emitting diode driver |
| CN104602393B (en) * | 2013-10-31 | 2017-12-15 | 株式会社搜路研 | LED drive |
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| 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: 20111228 Termination date: 20160729 |
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| CF01 | Termination of patent right due to non-payment of annual fee |