Patent ID: 7307462
Filing Date: 2007-12-11
Classification: H02M,Y02B

Abstract:
1. An IC controller for operating a transistor half bridge having two series connected transistors, comprising: an oscillator circuit for supplying a fixed frequency sawtooth oscillation signal and a first pulse signal at the fixed frequency; a soft start circuit coupled to the oscillator to receive the oscillation signal and produce a pulse length modifying signal to modify a second pulse signal derived from the oscillation signal to vary a length of a pulse in the second pulse signal; the soft start circuit being selectively operable to modify the second pulse signal; and a pulse steering circuit providing the second pulse signal, the second pulse signal comprising two complementary pulse signals, the pulse steering circuit inserting a dead time between the complementary pulse signals for driving the transistors of the half bridge in accordance with a width of pulses in the first pulse signal; a driver circuit for receiving the second pulse signal and providing outputs suitable for operating the transistors, and wherein the output of the soft start circuit is added together with the sawtooth oscillation signal to vary the width of pulses supplied to the driver circuit in a soft start mode.