Startup circuit including first and second Schmitt triggers and power converter employing the same

摘要

A startup circuit with reduced power dissipation, method of operating the same and a power converter employing the startup circuit. In one embodiment, the startup circuit for a controller includes a charge accumulation circuit having a resistor series-coupled to a capacitor and a first Schmitt trigger having an input coupled to the capacitor. The startup circuit also includes a second Schmitt trigger having an input coupled to an output of the first Schmitt trigger and configured to provide a bias voltage for the controller via the capacitor when an input voltage thereto exceeds a trip voltage.

主权项

1. A startup circuit for a controller, comprising:
a charge accumulation circuit having a resistor series-coupled to a capacitor; a first Schmitt trigger having an input coupled to said capacitor; a second Schmitt trigger having an input and a bias input coupled to an output of said first Schmitt trigger and configured to provide a bias voltage to power said controller via said capacitor when an input voltage thereto exceeds a trip voltage.