Pulse width modulation type constant current source circuit

Abstract

The invention discloses a pulse width modulation type constant current source circuit. The circuit comprises a reference voltage generation circuit and a V/I conversion circuit. The reference voltagegeneration circuit comprises an amplitude conversion circuit, a filter circuit, a voltage amplification buffer circuit and a parallel linear control circuit. The PWM control signal enables an output waveform to be switched between reference voltage VREF and 0V (ground) after passing through the amplitude conversion circuit, a signal output by the amplitude conversion circuit is output as direct current voltage after passing through the filter circuit, the direct current voltage is output after being amplified and isolated, and current driving is provided for output of the reference voltage generation circuit. The V/I conversion circuit comprises a summation operation circuit, a complementary driving circuit, a power amplification circuit, a detection resistor and a feedback loop, the V/I conversion circuit introduces current negative feedback into the amplification circuit, the detection resistor converts current into voltage, and feeds the voltage back to the summation operation circuit through the feedback loop, so that voltage-current conversion is realized. High-resolution and high-precision current output can be achieved by controlling PWM input signals.

Description

technical field [0001] The invention relates to the field of digital and analog circuits, in particular to a pulse width modulation type constant current source circuit. Background technique [0002] The constant current source is a common component in the control system. In addition to the common performance indicators such as output accuracy and current stability, which are gradually improved with the expansion of the application field, the demand for miniaturization and miniaturization is also increasing day by day. Commonly used program-controlled constant current source circuits generally use DA to generate a fixed voltage to achieve constant current output. To achieve higher output control accuracy, it is necessary to improve the DA output accuracy. In the implementation process, the controller needs to program and control the DA. The implementation cost is relatively expensive, the process is relatively complicated, and miniaturization and miniaturization cannot be ac...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a pulse width modulation type constant current source circuit, which solves the problems in the pri

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