CN205302075U - A linear control circuit of electric current for constant current source - Google Patents
A linear control circuit of electric current for constant current source Download PDFInfo
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- CN205302075U CN205302075U CN201521127804.4U CN201521127804U CN205302075U CN 205302075 U CN205302075 U CN 205302075U CN 201521127804 U CN201521127804 U CN 201521127804U CN 205302075 U CN205302075 U CN 205302075U
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Abstract
The utility model discloses a linear control circuit of electric current for constant current source, include: triode Q1, a field effect transistor U1, the 2nd field effect transistor U2, operational amplifier U3, first resistance R1, second resistance R2 and third resistance R3. Its output through with operational amplifier is connected with two field effect transistor's grid, and the source electrode through two field effect transistor arrive operational amplifier's second input again, forms a closed loop negative feedback, and voltage through adjusting the 3rd network node and give high level of a network node just can make the electric current of the 2nd a network node output definite value, has realized the linearity regulation of electric current source current, current value regulation convenience, and accommodation process steadily can not lead to the fact changing rapidly suddenly of circuit, it can prevent through setting up two field effect transistor that the electric current is too big, avoids damaging the electrical part, and the security is high. This circuit stable performance, the design is simple, low cost, the range of application is wide, is the selection that is widely used of simple constant current source.
Description
Technical field:
This utility model belongs to constant-current source circuit technical field, is specifically related to a kind of electric current linearity control circuit for constant-current source.
Background technology:
Constant-current source circuit seeks to provide a stable electric current to ensure the basis that other circuit stability works. Constant-current source circuit is mainly made up of input stage and output stage, and input stage provides reference current, the constant current that output stage output needs. Namely require constant-current source circuit output constant current, therefore should be the C-V characteristic with saturated output electric current as the device of output stage. BJT or MOSFET being typically with working in output current saturation state realizes. Existing constant-current source has two kinds, a kind of be the B2911A of high-precision source table such as Agilent of import, Advantest 6166 etc., another kind is the constant-current source circuit that user is built into various discrete or integrated chip. Although the high-precision source table precision of import is high, stability is high, single expensive, and volume is bigger, it is not easy to be integrated in embedded system; The precision of the constant-current source circuit that user is built into various discrete or integrated chip, stability meet general operational requirement, simple in construction, it is possible to be integrated in embedded system.
The constant-current source circuit being built into various discrete or integrated chip in prior art includes signal source circuit and electric current linearity control circuit, wherein, in existing electric current linearity control circuit, current value adjustment is inconvenient, adjustment process easily causes changing rapidly suddenly of circuit, very easily damaging electrical part, safety is poor.
Utility model content:
For this, technical problem to be solved in the utility model is in that in prior art for the electric current linearity control circuit of constant-current source, regulate inconvenience, adjustment process easily causes changing rapidly suddenly of circuit, electrical part is very easily damaged when electric current is excessive, safety is poor, thus proposing a kind of electric current linearity control circuit for constant-current source.
For reaching above-mentioned purpose, the technical solution of the utility model is as follows:
A kind of electric current linearity control circuit for constant-current source, including: audion Q1, the first field effect transistor U1, the second field effect transistor U2, operational amplifier U3, the first resistance R1, the second resistance R2.
The base stage of described audion Q1 connects first network node F1, the grounded emitter of described audion Q1 by the first resistance R1, and the colelctor electrode of described audion Q1 connects the grid of described first field effect transistor U1 and the grid of described second field effect transistor U2.
Described first field effect transistor U1 and described second field effect transistor U2 is connected in parallel, the drain electrode of described first field effect transistor U1 and the drain electrode of described second field effect transistor U2 are connected with the second network node F2 respectively, and the source electrode of described first field effect transistor U1 and the source electrode of described second field effect transistor U2 are respectively through the second resistance R2 ground connection.
First input end 5 foot of described operational amplifier U3 connects the 3rd network node F3, second input 6 foot of described operational amplifier U3 connects the source electrode of described first field effect transistor U1 and the source electrode of described second field effect transistor U2, and outfan 7 foot of described operational amplifier U3 connects the grid of described first field effect transistor U1 and the grid of described second field effect transistor U2.
Described first network node F1 is for controlling end, and described second network node F2 is current output terminal, and described 3rd network node F3 is voltage input end.
Preferred as technique scheme, the NPN type low-power transistor that described audion Q1 adopts model to be 9013.
Preferred as technique scheme, described first field effect transistor U1 and described second field effect transistor U2 adopt the insulated gate enhancement mode N-channel field effect transistor of same model specification.
Preferred as technique scheme, the two ends of described first field effect transistor U1 and the two ends of described second field effect transistor U2 connect radiating block respectively.
Preferred as technique scheme, outfan 7 foot of described operational amplifier U3 connects power supply by the 3rd resistance R3.
Preferred as technique scheme, described power supply is the power supply of power supply Cps-12V.
The beneficial effects of the utility model are in that: it is by connecting the outfan of operational amplifier and the grid of two field effect transistor, the second input of operational amplifier is arrived again by the source electrode of two field effect transistor, form a close loop negative feedback, by regulating the voltage of the 3rd network node and to one high level of first network node, just can make the electric current of the second network node output certain value, achieve the linear regulation of current source current, current value adjustment is convenient, regulate process stabilization, not resulting in changing rapidly suddenly of circuit, safety is high. The brightness of linear regulation LED, the magnetic field intensity of linear regulation electric magnet can be realized, linearly provide required current value etc.; It is by arranging two field effect transistor, it is possible to prevent electric current excessive, it is to avoid damage electrical part, and safety is high; It arranges radiating block by the two ends of scene effect pipe, it is possible to dissipate the heat of heating in time, it is ensured that the life-span of field effect transistor. This circuit performance is stable, and design is simple, and with low cost, applied range, is the choosing widely used of simple constant-current source.
Accompanying drawing illustrates:
The following drawings is only intended to, in this utility model being schematically illustrated and explaining, not limit scope of the present utility model. Wherein:
Fig. 1 is a kind of electric current linearity control circuit figure for constant-current source of one embodiment of this utility model.
Detailed description of the invention:
As it is shown in figure 1, the electric current linearity control circuit for constant-current source of the present utility model, including: audion Q1, the first field effect transistor U1, the second field effect transistor U2, operational amplifier U3, the first resistance R1, the second resistance R2, the 3rd resistance R3.
The base stage of described audion Q1 connects first network node F1, the grounded emitter of described audion Q1 by the first resistance R1, and the colelctor electrode of described audion Q1 connects the grid of described first field effect transistor U1 and the grid of described second field effect transistor U2. In the present embodiment, the NPN type low-power transistor that described audion Q1 adopts model to be 9013. The effect of described audion Q1 is the grid of the first field effect transistor U1 described in on-off control. Described first network node F1 is for controlling end, for controlling the break-make of described audion Q1, described first resistance R1 is current limliting base resistance, described first resistance R1 adopts the resistance of 330R/0603, the steady operation that described first resistance is described audion Q1 creates conditions, and it is effective that described audion Q1 base stage controls end high level.
Described first field effect transistor U1 and described second field effect transistor U2 is connected in parallel, the drain electrode of described first field effect transistor U1 and the drain electrode of described second field effect transistor U2 are connected with the second network node F2 respectively, described second network node F2 is current output terminal, and the source electrode of described first field effect transistor U1 and the source electrode of described second field effect transistor U2 are respectively through the second resistance R2 ground connection. In the present embodiment, described first field effect transistor U1 and described second field effect transistor U2 adopts the insulated gate enhancement mode N-channel field effect transistor of same model specification. When the colelctor electrode output low level of described audion Q1 is, because the source electrode of described first field effect transistor U1 and described second field effect transistor U2 are N-channel, low level turns on, between drain electrode and the source electrode of described field effect transistor, resistance is only small, it is negligible, adopt two field effect transistor, be to prevent electric current excessive, pipe can be burnt out. In the present embodiment, the two ends of described first field effect transistor U1 and the two ends of described second field effect transistor U2 connect radiating block respectively. The heat of field effect transistor heating can be dissipated in time, it is ensured that the life-span of pipe. In the present embodiment, described second resistance R2 is high-power resistance, and described second resistance R2 adopts the resistance of 0.5R/2512, and power is chosen critically important, otherwise can burn out resistance, is unlikely to make resistance too fast aging.
First input end 5 foot of described operational amplifier U3 connects the 3rd network node F3, described 3rd network node F3 is voltage input end, second input 6 foot of described operational amplifier U3 connects the source electrode of described first field effect transistor U1 and the source electrode of described second field effect transistor U2, and outfan 7 foot of described operational amplifier U3 connects the grid of described first field effect transistor U1 and the grid of described second field effect transistor U2. Outfan 7 foot of described operational amplifier U3 connects power supply by the 3rd resistance R3. Described 3rd resistance R3 is pull-up steady resistance, and described 3rd resistance R3 adopts the resistance of 10K/0603. Described power supply is the power supply of power supply Cps-12V. Optionally suitable voltage.
Operation principle:
Outfan 7 foot of operational amplifier U3 and two field effect transistor U1, the grid of U2 connects, by two field effect transistor U1, the source electrode of U2 arrives second input 6 foot of operational amplifier U3 again, form a close loop negative feedback, now, operational amplifier U3 is operated in linear amplification region, meet the short and empty broken strip part of the void in amplifier, the electric current of 5 feet and 6 feet that flow through operational amplifier U3 is ignored equal to 0, therefore the voltage of 5 feet of operational amplifier U3 and 6 feet is equal, regulate the voltage on 5 feet of operational amplifier U3, namely regulate the voltage on 6 feet of operational amplifier U3, again because to mono-high level of first network node F1, audion Q1 turns on, now, first field effect transistor U1 and the second field effect transistor U2 has been turned on, the described electric current flowing through the first field effect transistor U1 and the second field effect transistor U2 is equal to the voltage on 6 feet of operational amplifier U3 divided by the second resistance R2, from Ohm's law: the electric current obtained is the output electric current of the second network node F2, this is exported electric current and uses on the circuit such as adjustment LED luminance, good linear regulation effect can be obtained.
The electric current linearity control circuit for constant-current source described in the present embodiment, including: audion Q1, the first field effect transistor U1, the second field effect transistor U2, operational amplifier U3, the first resistance R1, the second resistance R2 and the three resistance R3. It is by connecting the outfan of operational amplifier and the grid of two field effect transistor, the second input of operational amplifier is arrived again by the source electrode of two field effect transistor, form a close loop negative feedback, by regulating the voltage of the 3rd network node and to one high level of first network node, just can make the electric current of the second network node output certain value, achieve the linear regulation of current source current, current value adjustment is convenient, regulate process stabilization, not resulting in changing rapidly suddenly of circuit, safety is high. The brightness of linear regulation LED, the magnetic field intensity of linear regulation electric magnet can be realized, linearly provide required current value etc.; It is by arranging two field effect transistor, it is possible to prevent electric current excessive, it is to avoid damage electrical part, and safety is high; It arranges radiating block by the two ends of scene effect pipe, it is possible to dissipate the heat of heating in time, it is ensured that the life-span of field effect transistor. This circuit performance is stable, and design is simple, and with low cost, applied range, is the choosing widely used of simple constant-current source.
Obviously, above-described embodiment is only for clearly demonstrating example, and is not the restriction to embodiment. For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description. Here without also cannot all of embodiment be given exhaustive. And the apparent change thus extended out or variation still in this utility model create protection domain among.
Claims (6)
1. the electric current linearity control circuit for constant-current source, it is characterised in that including: audion Q1, the first field effect transistor U1, the second field effect transistor U2, operational amplifier U3, the first resistance R1, the second resistance R2;
The base stage of described audion Q1 connects first network node F1, the grounded emitter of described audion Q1 by the first resistance R1, and the colelctor electrode of described audion Q1 connects the grid of described first field effect transistor U1 and the grid of described second field effect transistor U2;
Described first field effect transistor U1 and described second field effect transistor U2 is connected in parallel, the drain electrode of described first field effect transistor U1 and the drain electrode of described second field effect transistor U2 are connected with the second network node F2 respectively, and the source electrode of described first field effect transistor U1 and the source electrode of described second field effect transistor U2 are respectively through the second resistance R2 ground connection;
First input end 5 foot of described operational amplifier U3 connects the 3rd network node F3, second input 6 foot of described operational amplifier U3 connects the source electrode of described first field effect transistor U1 and the source electrode of described second field effect transistor U2, and outfan 7 foot of described operational amplifier U3 connects the grid of described first field effect transistor U1 and the grid of described second field effect transistor U2;
Described first network node F1 is for controlling end, and described second network node F2 is current output terminal, and described 3rd network node F3 is voltage input end.
2. the electric current linearity control circuit for constant-current source according to claim 1, it is characterised in that:
The NPN type low-power transistor that described audion Q1 adopts model to be 9013.
3. the electric current linearity control circuit for constant-current source according to claim 1, it is characterised in that:
Described first field effect transistor U1 and described second field effect transistor U2 adopts the insulated gate enhancement mode N-channel field effect transistor of same model specification.
4. the electric current linearity control circuit for constant-current source according to claim 3, it is characterised in that:
The two ends of described first field effect transistor U1 and the two ends of described second field effect transistor U2 connect radiating block respectively.
5. the electric current linearity control circuit for constant-current source according to claim 1, it is characterised in that:
Outfan 7 foot of described operational amplifier U3 connects power supply by the 3rd resistance R3.
6. the electric current linearity control circuit for constant-current source according to claim 5, it is characterised in that:
Described power supply is the power supply of power supply Cps-12V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521127804.4U CN205302075U (en) | 2015-12-30 | 2015-12-30 | A linear control circuit of electric current for constant current source |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521127804.4U CN205302075U (en) | 2015-12-30 | 2015-12-30 | A linear control circuit of electric current for constant current source |
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| Publication Number | Publication Date |
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| CN205302075U true CN205302075U (en) | 2016-06-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201521127804.4U Withdrawn - After Issue CN205302075U (en) | 2015-12-30 | 2015-12-30 | A linear control circuit of electric current for constant current source |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105404348A (en) * | 2015-12-30 | 2016-03-16 | 苏州博众精工科技有限公司 | Current linear control circuit for constant current source |
-
2015
- 2015-12-30 CN CN201521127804.4U patent/CN205302075U/en not_active Withdrawn - After Issue
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105404348A (en) * | 2015-12-30 | 2016-03-16 | 苏州博众精工科技有限公司 | Current linear control circuit for constant current source |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder | ||
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Address after: The Wujiang economic and Technological Development Zone West Road Wujiang District of Suzhou City, Jiangsu Province, No. 666 215200 Patentee after: Bo Seiko Polytron Technologies Inc Address before: The Wujiang economic and Technological Development Zone West Road Wujiang District of Suzhou City, Jiangsu Province, No. 666 215200 Patentee before: Suzhou Bozhong Precision Industry Technology Co., Ltd. |
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| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20160608 Effective date of abandoning: 20180216 |