POWER SUPPLY CIRCUIT

An improved power supply circuit which includes a utility power source, a plurality of silicon controlled rectifiers (SCR-SCR), 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 (Q˜Q). When the utility power source is in a positive half cycle, the SCR and the SCR are turned on; the SCR the SCR the SCR and the SCR are turned off; the Q is activated to make the electrical energy directed to the first capacitor through the diode of the Q and the voltage on the first capacitor is maintained at a constant. Meanwhile, the Q is turned off, the Q is operated to let the current flow through the second inductor to charge the second battery.