Patent ID: 8248114

Claim:
The method for maintaining an operating state of a circuit, comprising: storing energy in a first energy storage element in response to a first portion of a pulse, wherein storing the energy in the first energy storage element comprises: using the first portion of the pulse to close first and second switches, wherein closing the first switch electrically couples a first node to the first energy storage element; and charging the first energy storage element in response to a first voltage at the first node, wherein charging the first energy storage element includes subtracting a voltage that is across a current sensitive load from a drive signal to generate the first voltage at the first node; using the energy stored in the first energy storage element during a second portion of the pulse to generate an error signal; using the error signal to generate the drive signal; and generating the first voltage at the first node from the drive signal, and using the first voltage at the first node to charge a second energy storage element.