Starting circuit for electric discharge lamp
AssigneeBalboa Instruments, Inc.
InventorPatrick McElroy
Life of this patent
Estimating the term…
Abstract
A starting circuit for an electric discharge lamp providing an electric current to a lamp having a first and a second filament. The circuit measures a lamp current and a filament temperature and then compares these against a reference voltage. When the lamp current is below a set threshold value, a relay contact disposed between the first and second filament is closed to direct the electric current through the first and second filaments to initiate pre-heating of the lamp. Once the filament temperature exceeds a set threshold, the relay contact is opened and the electric current passes through heated gas inside the lamp.
Claims15
A starting circuit for an electric discharge lamp, comprising:
- an electric current provider;
- a lamp having a first and a second electrode, the first electrode being connected to the electric current provider;
- a filament control relay disposed between the first electrode and the second electrode, the filament control relay has a closed position to direct electric current through the first and second electrodes, and an open position to allow electric current to pass through the lamp from the first electrode to the second electrode;
- a sense resistor connected to the second electrode of the lamp;
- a peak voltage detector connected to the sense resistor, the peak voltage detector detects voltage across the sense resistor;
- a filament temperature peak voltage detector connected between the first electrode and the second electrode below the filament control relay, the filament temperature peak voltage detector detects voltage across the first and second electrodes;
- and
- a control logic component receiving signals from the peak voltage detector and the filament temperature peak voltage detector, the control logic component sets the filament control relay in the closed position when the current from the peak voltage detector is less than a first threshold value, and the control logic component resets the filament control relay in the open position when the current from the filament temperature peak voltage detector is greater than a second threshold value.
A starting circuit associated with an electric discharge lamp, comprising:
- a control relay associated with the electric discharge lamp;
- and
- a temperature detector controlling operation of the control relay;
- wherein the temperature detector initiates operation in the control relay so that electric current will pass through the lamp without needing an inductive kick.
A starting circuit for an electric discharge lamp, comprising:
- means for directing an electrical current to a lamp having a first and second filament;
- a control relay coupled between the first and second filaments, the control relay having an open position and a closed position;
- means for measuring the electrical current flowing through the first and second filaments;
- means for measuring a filament temperature;
- and
- means for positioning the control relay in the closed position when the measured electrical current is less than a first threshold value, and means for positioning the control relay in the open position when the measured filament temperature is greater than a second threshold value.
Dependencies are inferred from the claim text.