CIRCUIT FOR CONTROLLING OUTPUT OF RESONANCE-TYPE INVERTER

摘要

PURPOSE: A circuit for controlling an output of a resonance-type inverter is provided to prevent the variance of a resonance frequency by detecting a point that a switching voltage intersects with a zero voltage and a power voltage to control a switching duty ratio based on the point. CONSTITUTION: A heating unit(111) heats an object by means of an induced electromotive force generated by the switching of a power voltage. A synchronization detecting unit(112) detects the synchronization from the induced electromotive force of the heating unit(111). An output setting unit(114) sets a switching-on time. A duty setting unit(113) detects the synchronization of the synchronization detecting unit(112) to control the duty rate by the switching-on time of the output setting unit(114). A first driving unit(115) outputs a driving signal according to the duty rate from the duty setting unit(113). A first switching unit(116) resonates the heating unit(111) in response to the driving signal of the first driving unit(115). A second driving unit(118) outputs the driving signal according to the duty rate from the duty setting unit(113). A second switching unit controls a resonance period of the heating unit(111) in response to the driving signal of the second driving unit(118).