Patent ID: 9664714
Date: 2017-05-30
CPC Classifications: G01R,H02M

Claim:
1. A device for detecting input voltages and discharging residue voltages, comprising: a detection unit receiving a rectified DC input voltage, and according to fluctuations of the input voltage, generating a detection voltage signal having different logic levels; a triangle signal generator having a first capacitor, wherein in any one cycle of the input voltage at a moment the detection voltage signal changes from a first state to a second state, the first capacitor begins to charge, and in a following consecutive cycle of said any one cycle at a moment the detection voltage signal changes from the second state to the first state, the first capacitor begins to discharge; a reset signal generator having a second capacitor, wherein the second capacitor charges synchronously with the first capacitor and begins to discharge in the following consecutive cycle at a moment the detection voltage signal changes from the first state to the second state g, wherein the reset signal generator compares a varying voltage of the first capacitor and a varying voltage of the second capacitor and according to a comparison result triggers generation of a reset signal; an AC power removal and brown-out status determination unit comprising a counter, wherein within a preset period when the counter does not receive a first state reset signal and the voltage of the first capacitor is not lower than the voltage of the second capacitor, the AC power removal and brown-out status determination unit generates a brown-out detection signal indicating the input voltage at brown-out status; and when the voltage of the first capacitor is lower than the voltage of the second capacitor within the preset period, the AC power removal and brown-out status determination unit generates a power removal signal indicating the removal of the AC power supply.