Patent Number: 6,166,922

Title: Current oscillation control resonance circuit and power supply apparatus utilizing the same circuit

Abstract: A current detecting circuit detects amplitude of a current flowing toward the connecting point of a first transistor and a serial circuit through a second transistor and a comparing circuit compares amplitude of the current detected by the current detecting circuit with the reference value. An oscillation control circuit controls a control current supplied to an oscillating circuit in order to raise the oscillation frequency of the oscillating circuit when amplitude of the current detected by the current detecting circuit is smaller than the reference value as a result of comparison by the comparing circuit in view of preventing the oscillation frequency to be further lowered. Therefore, it is no longer required to design the apparatus by giving allowance to take into consideration the temperature characteristics and fluctuation of parts unlike the related art in which the minimum oscillation frequency of the oscillating circuit is set. Accordingly, variable range of the oscillation frequency can be expanded. As a result, it can be prevented that variable range of the oscillation frequency of the oscillating circuit becomes narrower.

Inventors: Kobori; Makoto (Miyagi, JP), Kaneko; Susumu (Miyagi, JP)

Assignee: Sony Corporation

International Classification: H02M 3/337 (20060101); H02M 3/24 (20060101); H02M 003/335 (); H02M 003/24 (); H02M 005/42 ()

Expiration Date: 12/26/2017