Resonant type constant voltage supply apparatus

• US 4,563,731 A
• Filed: 01/04/1983
• Issued: 01/07/1986
• Est. Priority Date: 01/07/1982
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Sato, Toshiaki, Kosaka, Masahiro, Maeda, Mikio
• Primary Examiner(s): BEHA JR, WILLIAM
• Application Number:
  US06/455,533
• Time in Patent Office: 1,099 Days
• Field of Search: 363/16, 363/17, 363/28, 363/29, 363/96, 363/98, 363/136
• US Class Current: 363/17
• CPC Class Codes: H02M 3/315 using semiconductor devices only
• CPC Class Codes: H02M 3/3382 in a push-pull circuit arrangement
• 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 resonant type constant voltage supply apparatus has a LC series resonance circuit. Energy stored in both a resonance capacitor and a resonance inductor is directly transferred to the output or input terminal of the apparatus. A control transformer is provided in parallel with the resonance capacitor for deriving the energy stored in the resonance capacitor. The amount of the energy stored in the resonance capacitor can be controlled by changing the switching frequency of the apparatus or the inductance of the control transformer, so as to thereby control the amount of energy transferred to the output or input terminal of the apparatus and thereby stabilize the output voltage of the apparatus.

Claims

1. A constant voltage supply apparatus comprising:

at least an input terminal for feeding an input direct current from an external direct current source;

at least a switching element connected in series with same input terminal for switching said input direct current;

a converter-transformer, a primary winding of said converter-transformer being connected in series with said switching element;

a resonance capacitor connected in series with said primary winding of said converter-transformer;

a common input terminal connected in series with said resonance capacitor;

a first rectifier circuit coupled to a secondary winding of said converter-transformer for producing a rectified signal from a signal appearing across terminals of said secondary winding of said converter-transformer;

a smooth circuit for smoothing said rectified signal so as to thereby obtain a dc output voltage;

a dc output terminal for feeding said dc output voltage to an external load;

a control transformer, a primary winding thereof being connected in parallel with said resonance capacitor, said control transformer further having a third winding for controlling an inductance of said control transformer by means of an electric signal fed thereto as a function of said dc output voltage; and

a second rectifier circuit coupled to a secondary winding of said control transformer for rectifying a voltage signal produced across said secondary winding of said control transformer and for directly feeding a rectified voltage to said dc output terminal of said apparatus.

2. A constant voltage supply apparatus according to claim 20, further comprising a switching element control means for controlling a switching frequency of said switching element as a function of said dc output voltage of said apparatus.