Patent ID: 9313830
Filing Date: 2016-04-12
CPC Classification: H05B

Claim Text:
1. A control circuit for controlling an induction heating cooker, which comprises an inductive coil, a bridge rectifier 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, wherein the bridge rectifier comprises a first terminal, a second terminal, a third terminal and a fourth terminal, the first terminal and the second terminal of the bridge rectifier being coupled to an AC voltage source, wherein the third terminal of the bridge rectifier outputs the power voltage, and the fourth terminal of the bridge rectifier outputs the 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 a node between the first terminal of the switch element and the inductive coil, 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 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, which is enabled when a voltage of the second input terminal is higher than the second reference voltage; and 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 and for stopping outputting the pulse when the stop signal is enabled.