Patent ID: 6385061
Filing Date: 2002-05-07
Classification: H02M,Y02B,Y10S

Abstract:
In a power conversion apparatus having a substantially direct current input voltage, an output transformer having a primary inductor and at least a secondary winding, and a transistor for controlling the transfer of energy from the primary inductor to the secondary winding and coupled to a controller for switching the transistor on and off at a predetermined rate, a sensor for sensing the power required at the output of the conversion apparatus and for generating a voltage representative thereof, a sensor for sensing the peak current in the primary inductor and for developing a voltage representative thereof, the controller containing a circuit for inhibiting selected on-cycles of the transistor, the circuit comprising:a comparator, a current source for developing a biasing voltage representative of the desired peak current in the primary inductor across a resistor external to the controller during the time when the transistor is switched off, means for receiving the voltage representative of the power required and for applying the voltage representative of the power required to the comparator, means for applying the biasing voltage to the comparator for comparing the biasing voltage to the voltage representative of the power required at the output, the output of the comparator coupled to the gate of the transistor for causing the transistor to skip on-cycles when the power required at the output is below the power the biasing voltage is representative of.