Power converter with active bleeding and ramp up-down delay and the method thereof

摘要

The present disclosure discloses a power converter providing a low output voltage from an offline AC. The power converter defines a voltage window for the input AC signal. Inside the voltage window, the rectified DC waveform is passed through to the output and the storage capacitor; outside the voltage window, the power converter is idle (or the output is blocked from input) and let the output storage capacitor alone supply the load.

主权项

1. A power converter, comprising:
an input port configured to receive an input AC signal; a rectifier coupled to the input port to receive the input AC signal, and based on the input AC signal, the rectifier provides a rectified DC signal; a storage port configured to provide a storage voltage; a storage capacitor coupled between the storage port and a reference ground to store energy; a first high voltage power device and a power switch device coupled in series between the rectifier and the storage port; and an active bleeding unit having a first input terminal, a second input terminal, a third input terminal and an output terminal, wherein the first input terminal is coupled to the storage port to receive the storage voltage, the second input terminal is configured to receive a voltage threshold, the third input terminal is coupled to a connection node of the rectifier and the first high voltage power device, and the output terminal is coupled to the storage port, wherein when the storage voltage falls to the voltage threshold, the active bleeding unit is turned on to pull down the rectified DC signal, and when the storage voltage is above the voltage threshold, the active bleeding unit is in an off state, wherein the active bleeding unit includes a comparator having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal is configured to receive the storage voltage, the second input terminal is configured to receive the voltage threshold, wherein based on the storage voltage and the voltage threshold, the comparator generates a comparison signal at the output terminal and the comparison signal is provided to a discharge switch.