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Circuit of constant current source

A constant current source and circuit technology, applied in the field of electronics, can solve the problems of high manufacturing cost, general batch consistency, and large PCB area, and achieve good output consistency, insensitive parameter dispersion, and good temperature compensation effect. Effect

Inactive Publication Date: 2006-07-05
HUAWEI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0017] The disadvantages of this kind of constant current source circuit are: high precision requirements for op amp bias resistors, general batch consistency, large PCB area occupied, and high manufacturing costs

Method used

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Examples

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no. 1 example

[0060] Figure 4 A circuit diagram of a PNP transistor constant current source circuit 40 according to the first embodiment of the present invention is shown.

[0061] In the PNP transistor constant current source circuit 40 according to the first embodiment of the present invention, the emitter of the first PNP transistor 402 is connected to the positive pole of the power supply 406 through the first resistor 404 (Rc), and the power supply 406 is used to provide a DC voltage, Its negative pole is grounded; the collector of the first PNP transistor 402 is used to output the forward current I out , the base of the first PNP transistor 402 is connected to the collector of the second PNP transistor 410 through the second resistor 408 (R1), and the base of the first PNP transistor 402 is also grounded through the third resistor 412; the second PNP transistor 410 The base and the collector are connected together, and the emitter of the second PNP transistor 410 ( R2 ) is connected...

no. 2 example

[0070] Figure 5 A circuit diagram of the NMOS field effect transistor constant current source circuit 50 according to the second embodiment of the present invention is shown.

[0071] and Figure 4 Compared with the illustrated PNP transistor constant current source circuit 40 according to the first embodiment of the present invention, the difference lies in that the PNP transistor is replaced by an NMOS field effect transistor.

[0072] In the NMOS field effect transistor constant current source circuit 50 according to the second embodiment of the present invention, the source of the first NMOS field effect transistor 502 is connected to the positive pole of the power supply 504, and the gate of the first NMOS field effect transistor 502 is connected to The gate of the second NMOS field effect transistor 506 and the drain of the first NMOS field effect transistor 502 are used to output the forward current I out , the gate of the second NMOS field effect transistor 506 is c...

no. 3 example

[0075] Figure 6 A circuit diagram of the NPN triode constant current source circuit 60 according to the third embodiment of the present invention is shown.

[0076] and Figure 4 Compared with the shown PNP transistor constant current source circuit 40 according to the first embodiment of the present invention, the difference is that the PNP transistor is replaced by an NPN transistor, and the circuit is adjusted accordingly.

[0077] In the NPN transistor constant current source circuit 60 according to the third embodiment of the present invention, the base of the first NPN transistor 602 is connected to the base of the second NPN transistor 604, and the emitter of the first NPN transistor 602 is connected to the second NPN transistor. The emitter of 604 is connected, grounded or connected to the negative pole of the second power supply 608 at the same time, the negative pole of the second power supply 608 is grounded, the collector of the first NPN transistor 602 is used f...

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Abstract

The invention provides a constant current source, comprising: a power supply for supplying a DC voltage; a first transistor, having three ends, where the third end of the first transistor is connected to that of a second transistor; and a second transistor, where its type is identical with that of the first one, and its first end is connected to the first end of the power supply, its second end is connected to the second end of the power supply and its third end is connected with its first or second end; as the third and second ends of the second transistor are interconnected, the first end of the first transistor is connected with that of the second transistor and the second end of the first transistor is used to output a first-direction current; as the third and first ends of the second transistor are interconnected, the first end of the first transistor is used to output a second-direction current and the second end of the first transistor is connected with that of the second transistor. The invention is insensitive to parameter discreteness of a constant current transistor, and has good output consistency and good temperature compensation effect.

Description

technical field [0001] The invention relates to electronic technology, in particular to a constant current source circuit. Background technique [0002] With the rapid development of electronic technology, constant current source circuits have been widely used. Constant current source circuits are mainly used in circuits that require high current stability, such as RF small signal amplifiers. [0003] In the process of mass production and processing of transistor constant current source circuits, due to the voltage V between the base and emitter of the triode BE(ON) Influenced by the dispersion or by the voltage V between the gate and drain of the MOS field effect transistor GS(ON) Influenced by the discreteness of the circuit, the output of the constant current source circuit will have a certain degree of discreteness between boards and batches. For those circuits that require high precision of the constant current source, certain technical means must be adopted to adjus...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G05F1/56G05F1/567
Inventor 代郁峰
Owner HUAWEI TECH CO LTD
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