Abstract: An improved power supply circuit which includes a utility power source, a plurality of silicon controlled rectifiers (SCR1-SCR6), a first battery, a second battery, a first inductor, a second inductor, a first capacitor, a second capacitor and a plurality of power switch elements (Q1˜Q4). When the utility power source is in a positive half cycle, the SCR1 and the SCR6 are turned on; the SCR2, the SCR3, the SCR4 and the SCR5 are turned off; the Q1 is activated to make the electrical energy directed to the first capacitor through the diode of the Q3, and the voltage on the first capacitor is maintained at a constant. Meanwhile, the Q2 is turned off, the Q4 is operated to let the current flow through the second inductor to charge the second battery.

Abstract: An improved power supply circuit which includes a utility power source, a plurality of silicon controlled rectifiers (SCR1-SCR6), a first battery, a second battery, a first inductor, a second inductor, a first capacitor, a second capacitor and a plurality of power switch elements (Q1˜Q4). When the utility power source is in a positive half cycle, the SCR1 and the SCR6 are turned on; the SCR2, the SCR3, the SCR4 and the SCR5 are turned off; the Q1 is activated to make the electrical energy directed to the first capacitor through the diode of the Q3, and the voltage on the first capacitor is maintained at a constant. Meanwhile, the Q2 is turned off, the Q4 is operated to let the current flow through the second inductor to charge the second battery.