Patent Number: 6,294,904

Title: Multiple frequency switching power supply and methods to operate a switching power supply

Abstract: A multiple frequency switching power supply including a pulse width modulation circuit having an output, having an input and having a clock signal input. The power supply also includes a switching transistor having first and second current-carrying electrodes and a control electrode. The first current-carrying electrode is coupled to a voltage source, the control electrode is coupled to the output of the pulse width modulation circuit and the second current-carrying electrode is coupled to a power supply output configured to provide a regulated output voltage. The power supply additionally includes a voltage sensing circuit coupled to the power supply output and having an output coupled to the pulse width modulation circuit input and a switch coupled to the clock input of the pulse width modulation circuit. The switch supplies a first clock signal having a first frequency when the power supply is in a normal mode of operation and supplies a second clock signal having a second frequency more than order of magnitude lower than the first frequency when the power supply is in a standby mode of operation.

Inventors: Hirst; B. Mark (Boise, ID)

Assignee: Hewlett-Packard Company

International Classification: G05F 1/10 (20060101); G05F 1/44 (20060101); H02M 3/04 (20060101); H02M 3/156 (20060101); G05F 001/40 ()

Expiration Date: 09/25/2018