Apple Inc.

Fairchild Semiconductor Corporation

David S Schoenwald

Charles O Forge

Steven Paul Sapp

A semiconductor bilateral switch that minimizes the on-state resistance by making a common-source connection between the switch transistors internal to the package. Wire bonds internally connecting the source electrodes of the transistors also provide the function of one or both of a current sense resistor and fuse element.

Semiconductor bilateral switch

Apparatus for operating electroluminescent panels. An electroluminescent panel is driven by a voltage source feeding a modified bridge driven by a pulse width modulated signal. By using a pulse frequency above the range of human hearing and a modulating signal that is a sine wave of the proper frequency for operating the panel, a sine wave is generated across the panel without requiring bulky low frequency magnetic components.

High efficiency supply for electroluminescent panels

Method and apparatus for providing bootstrapped gate drive voltage in a flyback switching power supply. Switching transients and ringing caused by leakage inductance and capacitance in the flyback transformer are captured and used to provide a boosted gate drive voltage for the flyback switch, resulting in lower on resistance and lower switching losses.

Flyback switching power supply with bootstrapped gate drive

Method and apparatus for producing an auxiliary voltage in a switching power supply. One or more auxiliary windings are coupled to the main inductor of the switching power supply. A synchronous switch is used in conjunction with the auxiliary winding to provide rectification and additionally provides waveform averaging which improves efficiency and voltage regulation over varying load conditions.

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Los Gatos, CA, United States of America

David S Schoenwald