RESONANT CONVERTER

摘要

PURPOSE: A resonant converter is provided to regularly control output current by alternately switching a pulse frequency modulation mode and a pulse width modulation mode. CONSTITUTION: A first frequency control part(210) controls operating frequencies according to a first error voltage. A second frequency control part(220) controls operating frequencies according to a second error voltage. A selective control part(230) controls either the first or the second frequency control part to operate. A frequency setting part(240) sets an operating frequency according to the first or second error voltage output from the first or second frequency control part. A triangular wave generating part(250) generates triangular wave synchronized with the operating frequency set by the frequency setting part. A voltage control part(260) outputs a third error voltage, the result of comparison between a voltage level at an output current sensing resistance of a power conversion circuit and a set third reference voltage level. A duty control part(270) comprises a comparator(272) and a duty setter(274) for setting a switching duty. A switching control part(280) transmits first and second switching signal for controlling switching of first and second switches according to a duty signal.