Patent ID: 6977485

Claim:
A battery charging and/or DC power supply circuitry comprising: a rectifier unit electrically connected with an AC power source for rectifying a positive full wave of said AC power source to a plurality of positive half waves; a control circuit having a microprocessor for predetermined calculation and control; a semiconductor switch unit having an SCR serially connected with an input terminal of an MOS switch and electrically connected with said rectifier unit; an MOS switch drive circuit electrically connected with a control terminal of said MOS switch and said control circuit for being controlled by said control circuit to turn on/off said MOS switch; a level-limiting circuit having an OP comparator and a Zener diode, said OP comparator having two input terminals electrically connected with said rectifier unit and said Zener diode, said Zener diode being electrically connected with an output terminal of said MOS switch, said OP comparator having an output terminal electrically connected with said control circuit and said MOS switch drive circuit for limiting a predetermined voltage level of said MOS switch; and an SCR drive circuit having a pulse transformer and a transistor, said transistor electrically connected with said control circuit and a first side of said pulse transformer, said pulse transformer having a second side electrically connected with a gate terminal of said SCR; wherein a battery can be electrically connected with said circuitry by its one terminal electrically connected with said MOS switch and the other terminal electrically grounded, and then said control circuit controls said MOS switch drive unit and said SCR drive circuit to further drive said semiconductor switch unit to be turned on/off and timing of charging to intercept charging current from said rectified positive half-wave power source for charging said battery.