Resistive feed rail generation in a power supply

Abstract

A circuit provides current from a high voltage output to a low voltage output through a resistor when a load at the low voltage output is removed. The resistor provides current to keep the VBL voltage above the set point of a switching regulator that provides output power to the VBL output. Accordingly, the regulator's output stage provides a switched 0% duty cycle output and saves power until a load is presented again. Presenting a signal to either a shutdown circuit or a sleep pin shuts down the entire controller until a load is presented again. A zener diode is used to clamp the VBL at a voltage higher than the set point of the controller to ensure that the controller operates with a 0% duty cycle output while in a no-load condition. The circuitry can be configured to operate in either a positive or negative powering scheme.

Dependencies are inferred from the claim text.