Current limited quasi-resonant voltage converting power supply

• US 4,964,028 A
• Filed: 10/26/1989
• Issued: 10/16/1990
• Est. Priority Date: 10/26/1989
• Status: Expired due to Fees

• Current Assignee: Gec-Marconi Electronics Systems Corporation
• Original Assignee: Plessey Electronics Systems Corporation
• Inventors: Spataro, Vincent J.
• Primary Examiner(s): Wong, Peter S.
• Application Number:
  US07/426,729
• Time in Patent Office: 355 Days
• Field of Search: 363/16, 363/20, 363/21, 363/95, 363/97, 363/131, 363/56
• US Class Current: 363/56.1
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• 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

A voltage converting power supply having current limiting characteristics wherein a flyback converter is operated in a load dependent half-wave mode. Constant pulse width switching at a variable rate is utilized for regulation and, by setting the maximum switching frequency, current limiting is achieved.

Claims

1. A voltage converting power supply having current limiting characteristics comprising:

input means for receiving electrical power at an input voltage;

output means including a flyback converter for providing electrical power at an output voltage;

controllable switch means for providing a current path to effect the transfer of power from said input means to said output means, wherein said switch means is controllable to provide said current path at a variable frequency and the amount of power being transferred is dependent on the frequency at which said current path is provided; and

control means for controlling said switch means including;

means for providing a reference voltage;

means for comparing said output voltage with said reference voltage and providing a comparison signal representative of the difference therebetween;

means utilizing said comparison signal for controlling the frequency at which said current path is provided to maintain said output voltage equal to said reference voltage;

means for operating said switch means in a half-wave mode; and

means for limiting the maximum frequency at which said current path is provided.

2. A power supply according to claim 1 wherein said control means effects the provision of said current path at a variable rate and wherein each provision of said current path is for a fixed time.