| 摘要 |
<P>PROBLEM TO BE SOLVED: To widen a range which permits power supply to a load in the lower-limit direction and conduct fine control, in an inverter which conducts constant current control by PWM for respective switches of a semiconductor switch circuit provided at a primary winding of a transformer of which a secondary winding is connected to the load. <P>SOLUTION: Constant current control is performed by PWM, and control by intermittent operation is also used. For the intermittent operation control, an error signal of PWM control is set at zero at the time of turning off the intermittent operation. At the time of turning on and off the intermittent operation, the error signal of the PWM control is decreased or increased gradually by charging or discharging capacitor charges in a feedback circuit. As a result, at both turning on and off the intermittent operation, the slow start and end of the constant current control by PWM are conducted. <P>COPYRIGHT: (C)2004,JPO |
