Claims
- 1. 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.
- 2. A switching power supply according to claim 1, further comprising:said first transformer having a first secondary winding and a second secondary winding; a first rectifying diode through which said first secondary winding being connecting connected to said rated load; a second rectifying diode through which said second secondary winding being connected to said light load; said second transformer having a third secondary winding; and a third rectifying diode through which said third secondary winding being connected to said light load.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9-332820 |
Dec 1997 |
JP |
|
Parent Case Info
This application is a division of pending application Ser. No. 09/204,456 filed Dec. 3, 1998.
US Referenced Citations (3)