General Electric Company

Xuefei Xie

Gang Yao

Bo Zhang

Chenghua Zhu

Ting Ting Zhang

Fanbin Wang

Peng Sun

Ballasts are presented with improved end-of-life (EOL) detection of lamp DC voltage components and protection circuits to facilitate user maintenance and extend lamp life using selective dimming with preheating when EOL conditions are detected.

Ballast with end-of-life protection for one or more lamps

The present disclosure thus provides a technique for providing multi-level operation of ballast circuitry for discharge lamps. In one version, an auxiliary capacitance is switched in and out of circuit by a user controlled switch for lower the frequency of the voltage from the inverter to the transformer resulting in lower power output to the lamps. In another version, the auxiliary capacitance may be switched in and out of circuit by a user operated switch wherein the capacitance is connected to the secondary or output winding of the transformer for selectively reducing power to the lamps for reduced illumination. In other versions, auxiliary inductances are selectively switched in and out of circuit to alter the frequency of the primary voltage to the transformer. In another version, an auxiliary winding is selectively switched in and out of the secondary of the transformer for providing normal and reduced level power to the lamps. In another version, a variable direct current power supply is provided to the coupled inductors of the ballast circuitry for user control of the power supply to the ballast circuitry.

Changing power input to a gas discharge lamp

Electronic ballasts and buck-boost DC-DC converters therefor are presented with a buck converter with two switching devices connected with two capacitances and two diodes to limit the individual switching device voltages to around half the converter DC input voltage or less.

Electronic ballast with step up/down power factor correction DC-DC converter suitable for high input voltage applications

An electronic ballast circuit having at least two distinct switching cycles also includes an anti-striation feature. More particularly the electronic ballast includes an input section configured to receive an input from a power source. A resonant section receives the signals from the input section in order to generate a resonant signal. An anti-striation component is connected within the electronic ballast circuit to affect operation of the resonant section, which results in an affected resonant signal. A switching arrangement is configured to receive the affected resonant signal from the resonant section and anti-striation component, and is further configured to generate an asymmetric output signal due to the affects of the anti-resonant component, wherein the anti-striation component causes parameters of the resonant section of the electronic ballast circuit to be different for different switching cycles of the electronic ballast circuit. An output section is provided to output the asymmetric output signal to a lamp system.

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Shanghai, China

Xuefei Xie