Patent ID: 6339262
Filing Date: 2002-01-15
Classification: H02M,Y02B

Abstract:
A switching power supply adapted for use with an input DC power supply comprising:a main power supply effective to supply electric power to a rated load; said main power supply including a first transformer; said first transformer having at least a first primary winding; said at least first primary winding connected to said DC power supply; a first semiconductor switch connected to said at least first primary winding; a first integrated circuit connected to said first semiconductor switch effective to drive and control said first semiconductor switch; a sub power supply effective to supply electric power to a light load substantially smaller than said rated load; said sub power supply including a second transformer; said second transformer having at least a second primary winding; said at least second primary winding connected to said DC power supply; a second semiconductor switch connected in series with said at least second primary winding; a second integrated circuit connected to said second semiconductor switch effective to drive and control said second semiconductor switch; and wherein said second semiconductor switch is switched ON and OFF and said first semiconductor switch is not driven in a waiting mode of operation.