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US 5,430,635 AGranted
High power factor electronic transformer system for gaseous discharge tubes
AssigneeBertonee Inc.
InventorGuang Liu
Life of this patent
Estimating the term…
Abstract
A cost-effective apparatus to improve the power factor of an AC line powered electronic transformer for powering gaseous discharge tubes uses an L-C filter link between a rectifier that provides DC voltage and an inverter for converting from DC to AC. The L-C filter link and the inverter function as a power factor correction stage, while at the same time converting DC voltage to AC voltage to drive gaseous discharge tubes.
Claims12
A high power factor electronic transformer system for use with a rectifier, comprising:
- an inverter circuit connected to a rectified voltage from the rectifier for producing a high-frequency voltage therefrom;
- a first capacitor connected across a first input terminal and a second input terminal of said inverter circuit;
- an inductor connected between the first input terminal of said inverter circuit and a first output terminal of the rectifier and a second output terminal of the rectifier being connected to said second input terminal of said inverter circuit;
- switch means with an open state and a closed state;
- said inverter circuit including a transformer having a secondary winding connected to a load and a primary winding connected at one end to said first input terminal of said inverter circuit and at a second end to said switch means;
- a second capacitor connected in parallel with said switch means;
- and
- control means for controlling said switch means so that a sinusoidal input current input to the rectifier remains substantially sinusoidal.
5 more elements
A high power factor electronic transformer system for a gaseous discharge tube, comprising:
- a rectifier circuit connected to an alternating current voltage source and producing a rectified voltage therefrom;
- an inverter circuit having positive and a negative input terminals and including a transformer for producing a high-frequency voltage;
- an inductor connected between a positive output terminal of said rectifier circuit and said positive input terminal of said inverter circuit;
- a first capacitor connected across said positive and negative input terminals of said inverter circuit;
- a semiconductor control switch;
- said transformer having a secondary winding connected to provide the high-frequency voltage to the gaseous discharge tube and a primary winding connected at one end to said positive input terminal of said inverter circuit and at a second end to a drain of said control switch;
- a source of said control switch connected to said negative input terminal of said inverter circuit and to said first capacitor;
- a second capacitor connected between said drain and said source of said semiconductor control switch;
- and
- means for controlling said semiconductor control switch connected to a gate of said switch, wherein an inductance of the transformer, a capacitance of the second capacitor, and a switching frequency of the means for controlling are chosen so that the semiconductor control switch will conduct electricity between the drain and the source when a voltage across the drain and the source is at a minimum, and whereby a sinusoidal input current input to said rectifier circuit remains substantially sinusoidal.
7 more elements
Dependencies are inferred from the claim text.