Abstract: An apparatus for clamping the voltage across rectifier diodes in a soft-switching DC/DC converter, wherein the clamping action is created by an additional winding coupled to the primary winding of the converter's transformer. This additional winding has fewer turns than the primary winding, is also coupled to the clamping diodes and effectively clamps the voltage across the rectifier diodes by transformer action. One preferred embodiment of the invention is for use with a full bridge converter. Another preferred embodiment is for use with a two switch forward converter.

Abstract: The present invention provides for an apparatus for clamping the voltage across rectifier diodes in a soft-switching DC/DC converter. The clamping action is created by an additional winding coupled to the primary winding of the converter's transformer, which has fewer turns than the primary winding. This additional winding, which is also coupled to the clamping diodes, effectively clamps the voltage across the rectifier diodes by transformer action. One preferred embodiment of the invention is for use with a full bridge converter. Another preferred embodiment is for use with a two switch forward converter.

Abstract: A boost converter for a power factor correction circuit having application in a DC power supply for telecommunication equipment. The boost converter has a pair of independently controlled switches such as MOSFET in series with an inductor. A capacitor is in parallel with each switch and the lossless resonant discharge of the capacitors by energy stored in the inductor eliminates switch losses at turn on. As a result the converter may be operated at higher frequencies, thereby reducing the size and cost of magnetic components in the power supply.

Abstract: A pulse width modulation control circuit utilizes a retriggerable monostable multivibrator as a high speed comparator which compares a reference waveform with a control signal level to effect variable termination of modulated output pulses. The control circuit finds particular applicability to pulse width modulated switched mode power supplies.