Constant current driving circuit

Abstract

The present invention discloses a constant current driving circuit. One end of a load L1 is connected to a load power source VCC1 and the cathode of a freewheeling diode D1, the other end of the load L1 is connected to one ends of sampling resistors R1 and R2, the other end of the sampling resistor R2 is connected to the A pin of an isolation chip U1, the other end of the sampling resistor R1 is connected with the anode of the freewheeling diode D1, the K pin of the U1 and the drain of a switch N1, the C pin of the U1 is connected with one ends of the resistors R5, R6 and the INPUT terminal of a control chip U3, the other end of the resistor R5 is connected with a power supply VCC3, the other end of the resistor R6 and the E pin of the U1 are grounded, the OUTPUT pin of the control chip U3 and the K pin of the isolation chip U2 are connected, the A pin of an isolated chip U2 is connected with one end of a resistor R7, the other end of the resistor R7 is connected with the power supply VCC3, the VCC pin of the isolation chip U2 is connected with a power supply VCC2, the OUT pin of the isolation chip U2 is connected with the gate of the switch N1, and the GND pin of the isolation chip U2 and the source of the switch N1 are grounded. The structure is simple, the driving current control is convenient, and the cost is low.

Description

technical field [0001] The invention relates to a driving circuit, in particular to a constant current driving circuit. Background technique [0002] With the development of society and the progress of industrial control, industrial automation control has been popularized and widely used in all walks of life, but these control output control parts are still dominated by ordinary switches, which can meet the requirements for occasions with low requirements, but It is obviously incompetent for control occasions with high precision requirements. At present, the constant current driving circuit is mainly composed of a dedicated chip, an isolation circuit and a protection circuit, and the circuit design is complicated and the cost is high. At the same time, it is difficult to control the driving current of the existing constant current driving circuit, it is difficult to realize the preset current curve for output, and the current lag time is long. Contents of the invention ...

AI Technical Summary

Problems solved by technology

[0002] With the development of society and the progress of industrial control, industrial automation control has been popularized and widely used in all walks of life, but these control output control parts are still dominated by ordinary switches, which can meet the requirements for occasions with low requirements, but For control occasions with high precision requirements, it is obviously incompetent

At present, the constant current drive circuit is mainly composed of dedicated chips, isolation circuits and protection circuits. The circuit design is complex and the cost is high.

At the same time, the driving current control of the existing constant current driving circuit is relatively difficult, and it is difficult to realize the preset current curve for output, and the current lag time is long

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