Discharge lamp lighting circuit
AssigneeKoito Manufacturing Co., Ltd.
InventorsMasayasu Ito, Hitoshi Takeda
Life of this patent
Estimating the term…
Abstract
A discharge lamp lighting circuit is provided with a DC power source circuit, a DC-AC conversion circuit, and start circuits. A primary circuit of a transformer in each start circuit has a capacitor and a switch element. When the voltage across the capacitor exceeds a threshold value, or when the switch element has electrical continuity, a high voltage is supplied separately to the discharge lamps from the primary coil through the secondary coil. A common voltage supply circuit supplies the voltage to the primary circuit of each start circuit from the DC power source circuit or the DC-AC conversion circuit.
Claims9
A discharge lamp lighting circuit comprising:
- a DC power source circuit to output a bipolar voltage of positive polarity and negative polarity in reference to the ground potential;
- a DC-AC conversion circuit for converting the DC voltage into an AC voltage and supplying the AC voltage to discharge lamps;
- start circuits provided respectively for each discharge lamp to generate a high voltage signal for each discharge lamp;
- and
- a common voltage supply circuit to supply a voltage to each start circuit.
A discharge lamp lighting circuit comprising:
- discharge lamps;
- a DC power source circuit to output a bipolar voltage of positive polarity and negative polarity in reference to the ground potential;
- a DC-AC conversion circuit to convert the DC voltage into an AC voltage, which is supplied to the discharge lamps;
- a plurality of switching elements in the DC-AC conversion circuit to switch the polarity of the voltage from the DC power source circuit and send the switched voltage to each discharge lamp;
- a drive circuit to control the switching of the switch elements;
- start circuits provided respectively for the discharge lamps to generate a high voltage signal for each discharge lamp;
- and
- a common voltage supply circuit to supply a voltage to each start circuit;
- a transformer in each start circuit including a magnetic substance and a primary coil and a secondary coil;
- and
- a primary circuit of the transformer comprising a serial circuit of a capacitor and a switching element, the serial circuit being connected in parallel to the primary coil of the transformer,
- wherein the common voltage supply circuit supplies a voltage from the DC power source circuit or the DC-AC conversion circuit to the primary circuit to charge the capacitor of the primary circuit of each start circuit.
Dependencies are inferred from the claim text.