Valley detection circuit and drive circuit

Abstract

A technique for detecting a valley timing at lower cost is described. A drive circuit comprises a peak voltage holder, a valley voltage holder, a center voltage generator, a monitor, and a detector. The peak voltage holder holds a peak voltage of an oscillating signal that is based on a voltage at a terminal of an inductor coupled to a switching element. The valley voltage holder holds a valley voltage of the oscillating signal. The center voltage generator generates a center voltage based on the peak voltage and the valley voltage. The monitor monitors the present value of the voltage at the terminal. The detector detects, as a valley timing, a timing at which a predetermined delay time has elapsed from a timing at which the monitored present value of the voltage at the terminal has fallen below the center voltage.

Dependencies are inferred from the claim text.