| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an inverter power supply control circuit of a high frequency heater capable of improving power factor of a power supply circuit as well as trackability and stability. <P>SOLUTION: The oscillation control signal generated by an inverter power supply control circuit 12 includes a waveform shaping signal composed of a reference voltage setting signal which so approximates the current waveform of an AC output power supply 1 to a sine wave as to generate a current on both sides of the waveform in response to fluctuation of PWM control signal, and a peak part adjusting signal of sine wave form which subtracts waveform peak part of the current waveform to approximate to the sine wave. So, even if the PWM control signal fluctuates, the power factor of the power supply circuit can be automatically improved to a certain level by approximating the current waveform of AC output of the AC power supply to a sine wave, for improved power supply efficiency. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
