Phase controlled regulated power supply

• US 4,423,478 A
• Filed: 07/20/1981
• Issued: 12/27/1983
• Est. Priority Date: 07/20/1981
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Mason, Lawrence J., Bullock, Randolph A.
• Primary Examiner(s): Pellinen, A. D.
• Application Number:
  US06/285,236
• Time in Patent Office: 890 Days
• Field of Search: 307/297, 307/355, 307/356, 315/151, 315/158, 315/159, 315/272, 315/287, 323/237, 323/238, 323/242, 323/299, 323/300, 323/303, 323/320, 323/321, 323/326, 363/89, 363/127
• US Class Current: 363/89
• CPC Class Codes: H05B 39/042 by measuring the incident light
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A circuit is provided for regulating the application of power to a load which is relatively insensitive to rapid power fluctuation of the type exemplified by typical AC line sources. In one embodiment, an AC line source is applied at a controlled rate to a tungsten lamp whose operation is controlled by a transistor switching network. The transistor operation, in turn, is controlled by comparing a portion of the rectified signal with a signal proportional to the light output of the lamp.

Claims

1. A phase-controlled power supply circuit for providing regulated dc power to a radiant energy-producing load, said power supply circuit adapted to compensate for the effects of rapid power fluctuations in the ac input line source, said circuit comprising:

rectifier means for converting ac input voltage to full wave rectified dc voltage,

means for generating a first output signal V_c representative of the radiant energy emanating from said load, said generating means including a photosensing device which generates a current proportional to the radiant energy from the load impinging thereon, a first amplifier for converting said current into a voltage output V₂ and a second amplifier for amplifying output V₂ to generate output signal V_c,

means for comparing output V_c with a portion of the rectified dc voltage to produce a second output V_o, said comparing means comprising a third amplifier means for comparing the signal V_c, received at the negative input of said third amplifier with a portion of the rectified dc voltage received at the positive input of said third amplifier, and

a transistor switching circuit coupled between said comparing means and said load, said switching circuit being adapted to be turned on and off at a rate determined by the rate of change of the level of signal V_o,

whereby the load is turned on and off at a rate consistent with the switching circuit.

2. The power supply circuit of claim 1 wherein said load is a tungsten lamp and said sensing device is a photodiode.

3. The power supply circuit of claim 1 wherein said transistor switching circuit includes a Darlington transistor.

4. The power supply circuit of claim 3 wherein said switching circuit further includes a high gain closed loop transconductance amplifier connected between said comparator means and said Darlington transistor.