| 摘要 |
PROBLEM TO BE SOLVED: To develop a DC output power supply having idling current of zero not by using a transformer and a three-terminal regulator but by using a MOSFET. SOLUTION: A node between C1 and AC of a circuit obtained by serially connecting an AC power supply AC, a diode D, a MOSFET Q and a capacitor C1 is considered as zero point as shown in figure 1. If voltage B is applied between gates of the zero point and the MOSFET Q, voltage of C1 becomes nearly equal to "voltage B minus threshold voltage of Q" and both ends of C1 become the DC output power supply. In the circuit, idling current of exciting current of the transformer and circuit current of the three-terminal regulator becomes nearly zero, current flows in from input if the current flows in a load circuit RL, however, the current from input is zero if the current of the RL is zero. COPYRIGHT: (C)2008,JPO&INPIT
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