Micrel, Incorporated

Charles A Casey

David Dearn

Cameron Jackson

Richard Zhu

A DC-to-DC, buck-boost voltage converter includes a duty cycle controller configured to generate control signals for a buck driver configured to drive first and second buck switching transistors at a buck duty cycle and to generate control signals for a boost driver configured to drive first and second boost switching transistors at a boost duty cycle. The duty cycle controller includes at least a duty cycle timer and an offset timer where the duty cycle controller applies the duty cycle timer and the offset timer to control transitions between the buck, the buck-boost and the boost operation modes of the voltage converter.

Buck-boost converter using timers for mode transition control

A bi-directional comparator compares two input signals and applies a hysteresis level to the smaller input signal only after the output signal switches logical states and when the two input signals are within a predetermined range of each other. In one embodiment, the hysteresis applied to the smaller input signal is removed when the two input signals are no longer within the predetermined range of each other.

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Doylestown, PA, United States of America

Charles A Casey