Voltage detection circuit and a method of detecting voltage changes

摘要

A power conversion system and a method for voltage change detection, specifically, relates to a detection circuit implemented in the AC-DC power converter, detect the voltage change. The AC input voltage is rectified to convert into a DC input voltage transmitted to a detection unit generating a detection voltage signal at different logical states corresponding to the input voltage changes. A charge current source unit is used for charging the capacitor when the detection voltage signal is in a second state and a discharge current source unit is used for discharging the capacitor when the detection voltage signal is in a first state. A primary comparator compares the voltage changes of the capacitor in the alternating charge and discharge processes with a critical zero potential and outputs a detection signal identifying the changing trend of the input voltage.

主权项

1. A voltage detection circuit comprising:
a rectifier circuit converting an AC voltage to a DC input voltage; a detection unit receiving the DC input voltage and generating a detection voltage signal of different states of logic level corresponding to fluctuations of the DC input voltage amplitude; a capacitor; a charge current source unit for charging the capacitor when the detection voltage signal is in a second state of logic level; a discharge current source unit for discharging the capacitor when the detection voltage signal is in a first state of logic level; and a primary comparator comparing a varying voltage of the capacitor in the alternating processes of charging and discharging with a critical zero potential and generating a detection signal that identifies a changing trend of the input voltage.