Patent ID: 7397204
Filing Date: 2008-07-08
Classification: C01B,H05B

Abstract:
1. 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.