Patent ID: 8378655

Claim:
A method of determining a pre-bias voltage by a switch mode controller at start up or at a power-on-reset, the method comprising: receiving by a switch mode controller an input voltage or a power-on-reset signal; generating a voltage reference having a predetermined voltage; comparing the voltage reference with a feedback voltage and outputting a start signal to an error circuit and a pre-bias initialization circuit when the voltage reference is greater than or equal to the feedback voltage; measuring an initial switching node voltage or an equivalent voltage and outputting an initial duty cycle signal to the error circuit upon receipt of the start signal by the pre-bias initialization circuit, the initial duty cycle set substantially equal to a ratio of an output voltage and the input voltage; and providing a voltage error signal to a pulse width modulator when the start signal and initial duty cycle are received by the error circuit, the pulse width modulator configured to provide a pulse width modulation signal to enable at least one switching transistor to switch to provide an output voltage and to delay providing of the pulse width modulation output signal until the start signal and the initial duty cycle signal are received by the error circuit.