An AC voltage sampling circuit for output power control and its design method

Abstract

The invention discloses an AC voltage sampling circuit for output power control and a design method thereof, including an AC voltage divider circuit, a second-order band-pass active filter circuit, a high-precision full-wave rectifier circuit, a comparator circuit and an isolation sampling circuit , where the AC input voltage is input to the AC voltage divider circuit, the output terminal of the AC voltage divider circuit is connected to the input terminal of the second-order band-pass active filter circuit, and the output terminal of the second-order band-pass active filter circuit is connected to the input terminal of the high-precision full-wave rectifier circuit , the output end of the high-precision full-wave rectifier is connected to the input end of the comparator circuit, and the output end of the comparator circuit is connected to the input end of the isolation sampling circuit. This method avoids the sampling delay of the switching power supply and the increase in cost caused by the sampling of the single-chip microcomputer on the primary side and then transmission to the secondary side, so that the on-board power supply can accurately reduce the power according to the input voltage.

Description

technical field [0001] The invention belongs to the field of electronic technology and mainly includes an AC voltage divider circuit, a second-order band-pass active filter circuit, a high-precision full-wave rectifier circuit, a comparator circuit, and an isolated sampling circuit; it relates to an AC voltage sampling circuit for output power control Circuits and their design methods. Background technique [0002] Switching power supply is a power supply that uses modern power electronics technology to control the time ratio of switching on and off to maintain a stable output voltage. A switching power supply generally consists of a pulse width modulation (PWM) control chip (IC), a transformer and a switching tube (MOSFET). With the development and innovation of power electronics technology, switching power supply technology is constantly innovating. At present, switching power supply is widely used in almost all electronic equipment due to its small size, light weight an...

AI Technical Summary

Problems solved by technology

This method firstly carries out filtering processing after sampling and transmits it to the control chip through the serial port, which has the defects of delay and inaccuracy. It is also necessary to increase the workload of R&D personnel

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