A regulated DC to DC power supply of reduced complexity which delivers increased power to the load. The improved circuitry substitutes an inductor for the usual inductor-capacitor-switching transistor arrangements, and drives the inverter circuitry so that the on-times of opposite inverter transistors overlap.

A fixed frequency pulse width modulated current fed inverter power supply with imbalance compensation provided by means of a primary inductor in the input circuit. Energy is coupled between the primary inductor in the input and secondary inductor windings in the output circuits to provide a balanced power supply with good efficiency.

A DC to DC converter is shown having an inductor with primary and secondary windings whose primary winding is serially connected to the center tap of the primary winding of a push-pull transformer. The primary of the transformer is then connected through its ends by a pair of transistor switches to ground while the ends of the secondary of the transformer connect through diodes to an output terminal. The ends of the secondary of the transformer also connect through diodes to the inductor secondary and then to the output terminal. The presence of the inductor prevents the voltage across the switches from becoming twice the input voltage as in conventional circuits. By equalizing the secondary to primary turns ratio between the inductor and transformer, it is possible to equalize the voltage output during the time intervals when the switches are on and off.

In an electric power converting apparatus utilized to convert the power of a storage battery into an AC voltage, step up the AC voltage by use of a step up transformer and rectify the secondary voltage of the transformer to directly operate a DC driving motor of a car or an AC motor through an inverter, a rectifier and an inverter are provided to energize the secondary of the transformer from a commercial source and another rectifier is provided on the primary side of the transformer to charge the storage battery.

An X-ray apparatus, after an AC output from an AC power source is rectified by a first rectifier circuit, supplies it to a primary winding side of a high-tension transformer through a bridge inverter. The bridge inverter includes first and second switching elements arranged at its first and second arms and operating as high-frequency choppers, a third switching element and first parallel circuit arranged at its third arm and forming a closed circuit together with the primary winding of the high-tension transformer, and a fourth switching element Q.sub.4 and second parallel circuit arranged at its fourth arm and forming a closed circuit together with the primary winding of the high-frequency transformer, the first parallel circuit being connected in series with the third switching element and comprised of a diode and resistor and the second parallel circuit being connected in series with the fourth switching element and comprised of a diode and resistor. An energy stored in the primary winding of the high-tension transformer is released through the closed circuit. A high-voltage output induced in the secondary winding of the high-tension transformer is applied to the X-ray tube through a second rectifier circuit. A voltage applied to the X-ray tube is detected at a voltage detection circuit and controlled in the feedback control circuit. Control signals are supplied to the respective arms of the bridge inverter so that the voltage to be applied to the X-ray tube becomes a predetermined value.