High-accuracy constant current source circuit

Abstract

The invention discloses a high-precision constant current source circuit, comprising a PNP transistor Q1 and an NPN transistor Q2, a resistor R1 connected to the emitter of the transistor Q1, a diode D1 whose negative pole is connected to the base of the transistor Q1, and a diode D1 connected to the anode And connect the resistor R2 of the resistor R1, the capacitor C1 connected to the base of the transistor Q2, the resistor R3 and the resistor R4 connected in series between the emitter of the transistor Q2 and the ground, and the negative electrode connected to the collector of the transistor Q1 and the positive electrode connected to the resistors R3 and R4 Between the Zener diode D2, wherein the other end of the resistors R1, R2 and capacitor C1 is connected to the power supply VCC, the collector of the transistor Q2 is connected to the base of the transistor Q1; the diode D2 uses a TL431 voltage regulator, and its reference terminal is connected to the transistor Q2 emitter. The invention adopts TL431 voltage stabilizing source as the core, and adopts two-stage triodes to assist in stepping down and stabilizing the current, so that the precision can be improved under the condition of ensuring a better working state, and it has better temperature characteristics.

Description

technical field [0001] The invention belongs to the technical field of electronic devices, and in particular relates to a high-precision constant current source circuit. Background technique [0002] In many precision instruments, electronic devices require high precision. These electronic devices are very sensitive to the power supply current. If the current fluctuates too much, it will reduce the working accuracy of the device, or damage the device and cause the equipment to fail. The existing constant current source circuit has poor precision and cannot meet the requirements of precision instruments, and the circuit structure is relatively complicated. Therefore, it is necessary to provide a constant current source circuit with a simple structure and high precision. Contents of the invention [0003] In order to overcome the deficiencies in the prior art, the present invention provides a high-precision constant current source circuit with ingenious design and simple str...

AI Technical Summary

Problems solved by technology

[0002] In many precision instruments, electronic devices require high precision. These electronic devices are very sensitive to the power supply current. If the current fluctuates too much, it will reduce the working accuracy of the device, or damage the device and cause the equipment to fail.

The existing constant current source circuit has poor accuracy and cannot meet the needs of precision instruments, and the circuit structure is relatively complicated. Therefore, it is necessary to provide a constant current source circuit with a simple structure and high precision.

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