| 摘要 |
<p>PROBLEM TO BE SOLVED: To perform always stable voltage supply to an operating means, independently of the kinds of loads. SOLUTION: A switching element control unit 12e turns on a first switching element 12a in synchronization with the rise in a zero-cross detection signal Vz of a zero-cross detecting element 17 and starts timing operation for a charging limit time t1, and a capacitor element 12d is charged by the pulsating output of a rectifier 11. It is possible to charge and discharge the capacitor element 12d at each half period of a commercial power source 1 even when configuration is simple, and stable power supply to a final control element 13 becomes attainable, by discharging the charge of the capacitor element 12d, when a time interval of the charging limit time t1 which is not larger than half the period of the commercial power source 1 elapses, even if a pulsating output outputted from the rectifier 11 changes, or a level difference is generated at every other half wave, and the charged voltage Vc of the capacitor element 12d does not reach a threshold voltage Vth of a voltage detector 12c, since the impedance of a load 2 changes by the polarity of an AC voltage supplied from the commercial power source.</p> |
