Power supply for gas discharge lamp
AssigneeEverbrite, Inc.
InventorsMark Kastner, Harry M. Pyne
Life of this patent
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Abstract
A power supply for a gas discharge lamp is claimed. An input circuit receives power from a power source. An output transformer having a primary winding and a secondary winding and has a lamp connected in circuit across the secondary winding. First and second power switches switch power to the primary winding. The driver drives the power switches at a drive frequency. A tuned LC resonant circuit having a resonant frequency is connected in circuit between the driver and the lamp. A controller generates control signals to the driver at a first frequency that is functionally related to the drive frequency, and regulates the lamp current by controlling the difference between the resonant frequency and the first frequency.
Claims75
A power supply for a gas discharge lamp, comprising:
- an input circuit that receives power from a power source;
- an output transformer, having a primary winding and a secondary winding, the lamp being connected in circuit across the secondary winding;
- first and second power switches that switch power to said primary winding;
- a driver that drives said switches at a drive frequency;
- a tuned LC resonant circuit having a resonant frequency, connected in circuit between said driver and said lamp;
- a controller that generates control signals to said driver at a first frequency that is functionally related to said drive frequency, and that regulates the lamp current by controlling the difference between said resonant frequency and said first frequency, whereby controlling said difference between said resonant frequency and said first frequency controls lamp brightness during normal lamp operation;
- and
- wherein said controller outputs said control signals at a drive frequency that is less than said resonant frequency, and wherein said controller detunes said LC circuit by reducing said drive frequency to thereby reduce said lamp current.
A method of regulating the lamp current to a gas discharge lamp, comprising:
- providing an output transformer having a primary winding and a secondary winding;
- providing a tuned LC resonant circuit having a resonant frequency that is connected to interact with said secondary winding;
- generating control signals at a first frequency;
- switching a pair of switches at a drive frequency that is functionally related to said first frequency;
- controlling the difference between said first frequency and said resonant frequency to regulate the current to said lamp within a selected range, whereby controlling the difference between said first frequency and said resonant frequency controls lamp brightness during normal lamp operation;
- providing a programmable controller;
- and
- running a software control routine to generate said control signals.
A power supply for powering a gas discharge lamp, the power supply being electrically connectable to a power source and to the lamp, the power supply comprising:
- a transformer and tuned LC circuit combination, the combination including
- a transformer having a primary winding and a secondary winding, and
- a tuned LC circuit including said primary winding and at least one capacitor electrically connected in a series relationship to said primary winding, the LC circuit having a resonant frequency;
- first and second switches that switch power from the power source, the switched power being provided to said LC circuit;
- a controller in communication with the first and second switches, the controller being configured to
- generate control signals at a control frequency, the control signals resulting in the first and second switches switching the power at a switch frequency, the switch frequency being functionally related to the control frequency, and
- regulate the lamp current by controlling the difference between said resonant frequency and said switch frequency, whereby controlling said difference between said resonant frequency and said switch frequency controls lamp brightness during normal lamp operation.
Dependencies are inferred from the claim text.