Patent ID: 8476563
Filing Date: 2013-07-02
Classification: H05B

Abstract:
1. A control circuit for controlling an induction heating cooker, which comprises an inductive coil and a switch element, wherein the inductive coil is coupled between a power voltage and a first terminal of the switch element, and a second terminal of the switch element is coupled to a common voltage, the control circuit comprising: a first comparator having a first input terminal coupled to a first terminal of the inductive coil, a second input terminal coupled to a second terminal of the inductive coil, and an output terminal for outputting a trigger signal; a second comparator having a first input terminal coupled to a first reference voltage, a second input terminal coupled to the first terminal of the switch element, and an output terminal for outputting a fading signal, which is enabled when a voltage of the second input terminal is higher than the first reference voltage; a pulse generator for outputting a pulse to control the switch element when the trigger signal is changed from a second logic level to a first logic level, and for reducing a pulse width of the pulse when the fading signal is enabled; a bridge rectifier comprising a first terminal, a second terminal, a third terminal and a fourth terminal, wherein the first terminal and the second terminal of the bridge rectifier are coupled to an AC voltage source, the third terminal of the bridge rectifier outputs the power voltage, and the fourth terminal of the bridge rectifier outputs the common voltage; and a third comparator having a first input terminal coupled to a second reference voltage, a second input terminal selectively coupled to the first terminal or the second terminal of the bridge rectifier, and an output terminal for outputting a stop signal, wherein: the stop signal is enabled when a voltage of the second input terminal is higher than the first reference voltage; the pulse generator is coupled to the output terminal of the third comparator and receives the stop signal; and the pulse generator stops outputting the pulse when the stop signal is enabled.