Abstract: A boost-type power factor correction circuit is disclosed in which output voltage of the convertor is proportional to the peak input voltage. To achieve this, the circuit includes a peak rectifier D2, C2 which senses peak input voltage and provides a reference to which the output voltage derived through resistors R3, R4 is compared to give an error signal dependent upon variation from the peak input voltage derived reference. The error signal is used to control a MOSFET switch 120 to provide an output voltage V.sub.out dependent upon the reference.

Abstract: A start circuit for starting the generation of pulse width modulated switching pulses is disclosed for use in a DC/DC switching converter power supply. The starting circuit is responsive to the initiation of a DC voltage source and starts the operation of a pulse generator. The starting circuit also includes a relaxation oscillator connected to the DC voltage source for periodically generating a start pulse at a predetermined frequency. Ongoing power is coupled to the pulse generator once the generator begins operation. The relaxation oscillator is selectively disabled when the pulse generator is powered by the ongoing power supplied by the power supply during normal operation. The start circuit further includes a delay function for delaying the disabling of the relaxation oscillator for a preselected period after shutdown of the power supply and includes a rapid start function for reducing the time between restoration of input power and the operation of the start circuit.

Abstract: A start circuit for a DC-DC switching converter power supply is disclosed and includes a relaxation oscillator connected to the DC voltage source for periodically generating a start pulse at a predetermined frequency. The start pulse is coupled to a power switch on the primary side of a power transformer and functions to cause the power switch to close for the duration of each start pulse. The secondary winding of the power transformer is coupled to an energy storage device such as a capacitor which stores the charge coupled across the power transformer each time a start pulse is generated. When sufficient energy has been stored in the capacitor in this manner, a circuit detects this energy level and causes the energy to be coupled to a pulse generator circuit also located on the secondary side of the power transformer.

Abstract: A start circuit for starting the generation of pulse width modulated switching pulses is disclosed for use in a DC/DC switching converter power supply. The starting circuit is responsive to the initiation of a DC voltage source and starts the operation of a pulse generator. The starting circuit also includes a relaxation oscillator connected to the DC voltage source for periodically generating a start pulse at a predetermined frequency. Ongoing power is coupled to the pulse generator once the generator begins operation. The relaxation oscillator is selectively disabled when the pulse generator is powered by the ongoing power supplied by the power supply during normal operation. The start circuit further includes a delay function for delaying the disabling of the relaxation oscillator for a preselected period after shutdown of the power supply and includes a rapid start function for reducing the time between restoration of input power and the operation of the start circuit.