Power supply with power factor correction circuit

• US 5,691,890 A
• Filed: 11/27/1996
• Issued: 11/25/1997
• Est. Priority Date: 12/01/1995
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hyde, Richard Charles
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Vu, Bao Q.
• Application Number:
  US08/758,602
• Time in Patent Office: 363 Days
• Field of Search: 363/89, 363/16, 363/21, 363/20, 363/56, 363/131, 323/207
• US Class Current: 363/89
• CPC Class Codes: H02M 1/4258 using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage H02M1/4241 takes precedence
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Disclosed is a power supply which includes a transformer having a primary winding and a secondary winding. A rectifier circuit rectifies an input AC mains signal to produce a DC rectified mains signal. A power factor correction circuit transfers electrical power from the rectifier circuit to the primary winding. A switch is provided for transferring electrical power from the primary winding to the secondary winding. The power factor correction circuit includes a first diode having an anode connected to the rectifier circuit and a cathode connected to one end of the primary winding and a second diode having an anode connected to the rectifier circuit and a cathode connected to said one end of the primary winding via a snubber network. The correction circuit may also include a third diode having an anode connected to the rectifier circuit and a cathode connected to a second end of the primary winding via an inductor.

Claims

1. A power supply comprising:

a transformer having a primary winding and a secondary winding,

rectifier means for rectifying an input AC mains signal to produce a DC rectified mains signal,

a power factor correction circuit for transferring electrical power from the rectifier means to the primary winding,

means for transferring electrical power from the primary winding to the secondary winding, and

wherein the power factor correction circuit includes a first diode having an anode connected to the rectifier means and a cathode connected to one end of the primary winding and a second diode having an anode connected to the rectifier means and a cathode connected to a second end of the primary winding via an inductor.

2. The power supply of claim 1, wherein said power factor correction circuit further includes a third diode having an anode connected to the rectifier means and a cathode connected to said one end of the primary winding via a snubber network.