CN103687234A - Voltage controlled constant current source circuit with good stability - Google Patents
Voltage controlled constant current source circuit with good stability Download PDFInfo
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- CN103687234A CN103687234A CN201310678854.0A CN201310678854A CN103687234A CN 103687234 A CN103687234 A CN 103687234A CN 201310678854 A CN201310678854 A CN 201310678854A CN 103687234 A CN103687234 A CN 103687234A
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Abstract
Provided is a voltage controlled constant current source circuit with good stability. The positive input end of a comparator U1 of the voltage controlled constant current source circuit is connected with the ground, the negative input end of the comparator U1 is connected with an input voltage Vi through a resistor R1, the output end of the comparator U1 is connected with the input end of a driving circuit, the output end of the driving circuit is connected with the positive input end of a comparator U3 through an R14 and an R8 which are connected in series in sequence, the R14 and the R8 are connected with the ground through an R15, the negative input end of the comparator U3 is connected with the output end of the comparator U3 through an R9, the output end of the comparator U3 is connected with the negative input end of a comparator U2 through an R10, the negative input end of the comparator U2 is connected with the output end of the comparator U2 through an R11, the output end of the comparator U2 is connected with the output end of a resistor driving circuit through an R13 and the R14 which are connected in series in sequence, and the comparator U1 is connected with the common end of the R13 and an R2 though a guide wire. The voltage controlled constant current source circuit is simple in structure, the overall circuit stability is strong, and signal driving capacity is strong.
Description
Technical field
The present invention relates to a kind of constant-current control circuit, belong to electricity field.
Background technology
The controlled constant-current source circuit of good stability is the important component part of LED drive circuit, and its function is by adjusting, to control voltage to reach the control to electric current, and its performance has determined the degree of stability of LED brightness.
The controlled constant-current source circuit of good stability is because needs keep constant current, structure is comparatively complicated, higher to circuit structure and circuit elements requirement on devices, during use, need to keep stable operational environment, this has brought problems just to the design of the controlled constant-current source circuit of good stability.
Summary of the invention
The invention provides a kind of controlled constant-current source circuit of good stability, when reducing complexity in circuits, improved the stability of circuit, improve the driving force of circuit, solved the controlled constant-current source circuit complex structure of good stability, the problem of poor stability in the past.
For solving above-mentioned technical problem, the present invention is by the following technical solutions: the controlled constant-current source circuit of good stability, comprise comparator U1, comparator U2 and comparator U3, the positive input terminal ground connection of comparator U1, the negative input end of described comparator U1 connects input voltage Vi by resistance R 1, the output of described comparator U1 connects the input of drive circuit, the output of drive circuit is connected the positive input terminal of described comparator U3 by the resistance R 14 being connected in series successively with resistance R 8, between described resistance R 14 and resistance R 8, also pass through resistance R 15 ground connection, the negative input end of described comparator U3 connects the output of comparator U3 by resistance R 9, the output of described comparator U3 connects the negative input end of described comparator U2 by resistance R 10, the positive input terminal of described comparator U2 is by resistance R 12 ground connection, the negative input end of described comparator U2 is connected to the output of comparator U2 by resistance R 11, the output that the output of comparator U2 is connected to resistance drive circuit by the resistance R 13 that is connected in series successively and resistance R 14, the negative input level of described comparator U1 is connected to the common port of resistance R 13 and resistance R 2 by wire.
Described drive circuit comprises triode Q1 and triode Q2, the base stage of triode Q1 connects positive supply+15V by resistance R 4, and the base stage of triode Q1 is connected with the output of comparator U1 simultaneously, the collector electrode of described triode Q1 connects described positive supply+15V by resistance R 6, the emitter output of described triode Q1 is connected with resistance R 14, the base stage of described triode Q2 connects the output of comparator U1, the emitter of the emitter connecting triode Q1 of described triode Q2, the collector electrode of described triode Q2 connects negative supply-15V, negative supply-15V is also connected to the base stage of triode Q2 by resistance R 5.
Between the output of described triode Q1 and resistance R 14, be also connected with resistance R 7.
The resistance of described resistance R 4, resistance R 5 and resistance R 6 all equates.
Described comparator U1, comparator U2 and comparator U3 all adopt LM358 type amplifier.
Compared with prior art, the invention has the beneficial effects as follows: the controlled constant-current source circuit of this good stability of the present invention's design, not only simple in structure, and also integrated circuit stability is strong, and current driving ability is strong.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.
Fig. 1 is schematic diagram of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the present invention is further illustrated.
Embodiment 1
The controlled constant-current source circuit of good stability as shown in Figure 1, comprise comparator U1, comparator U2 and comparator U3, the positive input terminal ground connection of comparator U1, the negative input end of described comparator U1 connects input voltage Vi by resistance R 1, the output of described comparator U1 connects the input of drive circuit, the output of drive circuit is connected the positive input terminal of described comparator U3 by the resistance R 14 being connected in series successively with resistance R 8, between described resistance R 14 and resistance R 8, also pass through resistance R 15 ground connection, the negative input end of described comparator U3 connects the output of comparator U3 by resistance R 9, the output of described comparator U3 connects the negative input end of described comparator U2 by resistance R 10, the positive input terminal of described comparator U2 is by resistance R 12 ground connection, the negative input end of described comparator U2 is connected to the output of comparator U2 by resistance R 11, the output that the output of comparator U2 is connected to resistance drive circuit by the resistance R 13 that is connected in series successively and resistance R 14, the negative input level of described comparator U1 is connected to the common port of resistance R 13 and resistance R 2 by wire.
In the present embodiment, U3, R8 and R9 form voltage follower, and operation amplifier utensil high input impedance, can think that U3 does not have shunting action, and the electric current of the V2 that flows through all flows into load R15, and has V3=V2.U2 and resistance R 10, R11, R12 forms inverter, V4=-V3=-V2, U1 and resistance R 1, R2, R3, R13 forms reverse adder circuit, input signal is respectively Vi and V4, output voltage V 1=-(Vi+V4), again due to V4=-V2, so output voltage V 1=-(Vi-V2), operational amplifier U3 there is no shunting action, therefore the voltage at resistance R 14 two ends is V14=V1-V2=-Vi, the electric current of R14 and load R15 of flowing through equates, be all I=V14/R14=-Vi/R14, electric current in load is determined jointly by input voltage Vi and resistance R 14, as long as these two amounts are constant, it is constant that electric current will keep, by changing output voltage, get final product the electric current on regulating load R15, and drive circuit can amplifier comparator U1 output current, increasing circuit driving force, the present embodiment, when having simplified circuit, has improved the stability of circuit integral body, and electric current can be always constant, and the driving force of circuit also increases, and practicality greatly improves.
Embodiment 2
The present embodiment has increased following structure on the basis of embodiment 1: described drive circuit comprises triode Q1 and triode Q2, the base stage of triode Q1 connects positive supply+15V by resistance R 4, and the base stage of triode Q1 is connected with the output of comparator U1 simultaneously, the collector electrode of described triode Q1 connects described positive supply+15V by resistance R 6, the emitter output of described triode Q1 is connected with resistance R 14, the base stage of described triode Q2 connects the output of comparator U1, the emitter of the emitter connecting triode Q1 of described triode Q2, the collector electrode of described triode Q2 connects negative supply-15V, negative supply-15V is also connected to the base stage of triode Q2 by resistance R 5.
In the present embodiment, by triode Q1 and triode Q2, jointly the output current of comparator U1 is increased, from the current capacity of triode Q1 and triode Q3 output, be greater than the current capacity of comparator U1 output, thereby increased output driving force, improved current stability.
Embodiment 3
The present embodiment has increased following structure on the basis of embodiment 2: between the output of described triode Q1 and resistance R 14, be also connected with resistance R 7.
The resistance R 7 of the present embodiment, for voltage stabilizing, guarantees the voltage stabilization of V1, thereby can better stablize the electric current of R14.
Embodiment 4
The present embodiment has been done following optimization on the basis of above-mentioned arbitrary embodiment: the resistance of described resistance R 4, resistance R 5 and resistance R 6 all equates.
In the present embodiment, resistance R 4, resistance R 5 and resistance R 6 are got to similar resistance, can guarantee that triode Q1 and triode Q2, all in identical operating state, guarantee the two fan-out capability, also can improve the stability of drive circuit simultaneously.
Embodiment 5
Embodiment 5 is optimum embodiment of the present invention
The present embodiment has been done following optimization on the basis of above-mentioned arbitrary embodiment: described comparator U1, comparator U2 and comparator U3 all adopt LM358 type amplifier.
In the present embodiment LM358 type amplifier include two independently, the dual operational amplifier of high-gain, internal frequency compensation, price is low, excellent performance, the gain that can improve signal amplification circuit.
Be as mentioned above embodiments of the invention.The present invention is not limited to above-mentioned execution mode, and anyone should learn the structural change of making under enlightenment of the present invention, and every have identical or close technical scheme with the present invention, within all falling into protection scope of the present invention.
Claims (5)
1. the controlled constant-current source circuit of good stability, it is characterized in that: comprise comparator U1, comparator U2 and comparator U3, the positive input terminal ground connection of comparator U1, the negative input end of described comparator U1 connects input voltage Vi by resistance R 1, the output of described comparator U1 connects the input of drive circuit, the output of drive circuit is connected the positive input terminal of described comparator U3 by the resistance R 14 being connected in series successively with resistance R 8, between described resistance R 14 and resistance R 8, also pass through resistance R 15 ground connection, the negative input end of described comparator U3 connects the output of comparator U3 by resistance R 9, the output of described comparator U3 connects the negative input end of described comparator U2 by resistance R 10, the positive input terminal of described comparator U2 is by resistance R 12 ground connection, the negative input end of described comparator U2 is connected to the output of comparator U2 by resistance R 11, the output that the output of comparator U2 is connected to resistance drive circuit by the resistance R 13 that is connected in series successively and resistance R 14, the negative input level of described comparator U1 is connected to the common port of resistance R 13 and resistance R 2 by wire.
2. the controlled constant-current source circuit of good stability according to claim 1, it is characterized in that: described drive circuit comprises triode Q1 and triode Q2, the base stage of triode Q1 connects positive supply+15V by resistance R 4, and the base stage of triode Q1 is connected with the output of comparator U1 simultaneously, the collector electrode of described triode Q1 connects described positive supply+15V by resistance R 6, the emitter output of described triode Q1 is connected with resistance R 14, the base stage of described triode Q2 connects the output of comparator U1, the emitter of the emitter connecting triode Q1 of described triode Q2, the collector electrode of described triode Q2 connects negative supply-15V, negative supply-15V is also connected to the base stage of triode Q2 by resistance R 5.
3. the controlled constant-current source circuit of good stability according to claim 2, is characterized in that: between the output of described triode Q1 and resistance R 14, be also connected with resistance R 7.
4. the controlled constant-current source circuit of good stability according to claim 1, is characterized in that: the resistance of described resistance R 4, resistance R 5 and resistance R 6 all equates.
5. the controlled constant-current source circuit of good stability according to claim 1, is characterized in that: described comparator U1, comparator U2 and comparator U3 all adopt LM358 type amplifier.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310678854.0A CN103687234A (en) | 2013-12-14 | 2013-12-14 | Voltage controlled constant current source circuit with good stability |
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| CN201310678854.0A CN103687234A (en) | 2013-12-14 | 2013-12-14 | Voltage controlled constant current source circuit with good stability |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102723658A (en) * | 2012-04-23 | 2012-10-10 | 四川马尔斯科技有限责任公司 | Constant current source power supplying circuit of laser |
| CN103412600A (en) * | 2013-08-15 | 2013-11-27 | 浪潮电子信息产业股份有限公司 | Field programmable gate array (FPGA) based numerically-controlled direct-current constant current source |
| CN203706004U (en) * | 2013-12-14 | 2014-07-09 | 成都国蓉科技有限公司 | Voltage-controlled constant current source circuit |
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2013
- 2013-12-14 CN CN201310678854.0A patent/CN103687234A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102723658A (en) * | 2012-04-23 | 2012-10-10 | 四川马尔斯科技有限责任公司 | Constant current source power supplying circuit of laser |
| CN103412600A (en) * | 2013-08-15 | 2013-11-27 | 浪潮电子信息产业股份有限公司 | Field programmable gate array (FPGA) based numerically-controlled direct-current constant current source |
| CN203706004U (en) * | 2013-12-14 | 2014-07-09 | 成都国蓉科技有限公司 | Voltage-controlled constant current source circuit |
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Application publication date: 20140326 |