초록 ▼

An induction heating apparatus includes an inverter (5) which is driven by a DC power supply (3), and the inverter (5) includes a heating coil (9) and a switching transistor (11) which is connected thereto in series. The switching transistor (11) is turned on or off by a control circuit (35) to cont

An induction heating apparatus includes an inverter (5) which is driven by a DC power supply (3), and the inverter (5) includes a heating coil (9) and a switching transistor (11) which is connected thereto in series. The switching transistor (11) is turned on or off by a control circuit (35) to control a current flowing through the heating coil (9). The control circuit (35) takes a collector voltage of this switching transistor (11) from the point where the heating coil (9) and the switching transistor (11) are connected in series through a terminal (39). An integrated voltage of this collector voltage is generated in the control circuit (35), and the collector voltage is compared with the integrated voltage. When the former becomes lower than the latter, after a certain delay time, a switching signal is outputted from the control circuit (35), and the switching transistor (11) is turned on. Such a delay time is preferably varied in response to the magnitude of the collector voltage.

대표청구항 ▼

An induction heating apparatus comprising: a heating coil, a source of dc voltage having positive and negative voltage terminals, said positive terminal being connected to one end of said heating coil, a switching device which is connected between another end of said heating coil and said negative t

An induction heating apparatus comprising: a heating coil, a source of dc voltage having positive and negative voltage terminals, said positive terminal being connected to one end of said heating coil, a switching device which is connected between another end of said heating coil and said negative terminal of said source of dc voltage, for controlling a current flowing through said heating coil, a voltage sensing means for sensing a voltage across terminals of said switching device, an integrating means for integrating said voltage across said terminals of said switching device sensed by said voltage sensing means, a comparing means for comparing said voltage across said terminals of said switching device with said integrated voltage, and a control means for controlling said switching device based on an output of said comparing means.