High efficiency high voltage power supply for gas discharge devices

• US 4,698,741 A
• Filed: 07/22/1985
• Issued: 10/06/1987
• Est. Priority Date: 07/22/1985
• Status: Expired due to Fees

• Current Assignee: Webster Electric Co., Inc. (Danfoss A/S)
• Original Assignee: Webster Electric Co., Inc. (Danfoss A/S)
• Inventors: Pacholok, David
• Primary Examiner(s): Salce, Patrick R.
• Assistant Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US06/757,540
• Time in Patent Office: 806 Days
• Field of Search: 315/239, 315/242, 315/DIG. 7, 363/18, 363/19, 363/20, 363/21, 363/97, 363/131, 323/289
• US Class Current: 363/131
• CPC Class Codes: H05B 41/2822 using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
• CPC Class Codes: Y10S 315/07 Starting and control circuits for gas discharge lamp using transistors

Abstract

A high efficiency, low cost solid state power supply for gas discharge or other devices including a resonant oscillator having a high voltage transistor and a switching circuit connected to the high voltage transistor adapted to rapidly turn-off such transistor. The switching circuit including transistors interposed to interrupt the emitter current path of the high voltage transistor to force rapid cut-off thereof. The switching circuit coupled to the oscillator output tank capacitance which functions additionally as a differentiator to actuate the switching circuit.

Claims

1. A high voltage power supply for gas discharge or similar high voltage devices comprising a solid state oscillator, the oscillator including a high voltage bipolar transistor, an output transformer having primary, secondary, and feedback windings, the primary winding operatively connected to the collector of the high voltage transistor, the primary winding having an inductance, a capacitor operatively connected to the collector of the high voltage transistor, the capacitor and primary winding inductance forming a resonant output tank of said solid state oscillator, the secondary transformer winding adapted for connection to the gas discharge or similar high voltage device;

a first switching transistor operatively connected to the emitter of the high voltage transistor, said switching transistor adapted to selectively pass current from the emitter of the high voltage transistor only when the switching transistor is biased into conduction;

means operatively connected to the base input of the high voltage transistor for passing current therefrom;

bias means operatively connected to the high voltage and switching transistors for biasing said transistors into conduction, said bias means including the transformer feedback winding operatively interconnected to the high voltage and switching transistors to provide positive feedback bias to said transistors;

means for inhibiting conduction bias current to the switching transistor, said inhibiting means including differentiating means operatively connected to the collector output of the high voltage transistor for detecting increasing voltage levels thereon whereby the switching transistor is biased into non-conduction whenever the differentiator means detects an increasing voltage level on the collector of the high voltage transistor, the output tank capacitor is operatively connected to the switching transistor whereby said output tank capacitor functions as the differentiator means of the inhibiting means.