Discharge lamp lighting device, illumination device, and projector
First Claim
1. A discharge lamp lighting device, comprising:
- a direct current power source;
a chopper circuit capable of controlling an output power by performing DC-DC conversion with the direct current power source as a power source;
a smoothing capacitor connected between output terminals of the chopper circuit;
a polarity inversion circuit for performing DC-AC conversion with a voltage across the smoothing capacitor as a power source;
a high pressure discharge lamp to which an alternating voltage is applied by the polarity inversion circuit;
a control circuit for controlling an output of the polarity inversion circuit as well as an output power of the chopper circuit; and
a voltage detecting circuit for detecting a voltage corresponding to a lamp voltage of a high pressure discharge lamp, wherein a switch voltage for defining a range of voltages detected by the voltage detecting circuit is set in the control circuit, and the control circuit has a function of controlling the polarity inversion circuit such that an inversion frequency, at which the polarity of the lamp current of the high pressure discharge lamp is inverted according to a magnitude relation between the detected voltage and the switch voltage, is changed in plural stages.
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Accused Products
Abstract
In a chopper circuit, output power is controllable with a direct current power source as a power source, and a smoothing capacitor is connected between output terminals of the chopper circuit. A polarity inversion circuit applies an alternating voltage to a high pressure discharge lamp with a voltage across the smoothing capacitor as a power source. The output power of the chopper circuit and an inversion frequency of the polarity inversion circuit are controlled by a control circuit based upon a terminal voltage of the smoothing capacitor, which is detected by a voltage detecting circuit. In the control circuit, a switch voltage is set for defining a range of voltages detected by the voltage detecting circuit, and the inversion frequency is changed in plural stages according to the magnitude relation between the detected voltage and the switch voltage. The inversion frequency corresponding to electric power applied to the high pressure discharge lamp is set with respect to each range of lamp voltages, to thereby inhibit occurrence of an arc jump.
37 Citations
21 Claims
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1. A discharge lamp lighting device, comprising:
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a direct current power source;
a chopper circuit capable of controlling an output power by performing DC-DC conversion with the direct current power source as a power source;
a smoothing capacitor connected between output terminals of the chopper circuit;
a polarity inversion circuit for performing DC-AC conversion with a voltage across the smoothing capacitor as a power source;
a high pressure discharge lamp to which an alternating voltage is applied by the polarity inversion circuit;
a control circuit for controlling an output of the polarity inversion circuit as well as an output power of the chopper circuit; and
a voltage detecting circuit for detecting a voltage corresponding to a lamp voltage of a high pressure discharge lamp, wherein a switch voltage for defining a range of voltages detected by the voltage detecting circuit is set in the control circuit, and the control circuit has a function of controlling the polarity inversion circuit such that an inversion frequency, at which the polarity of the lamp current of the high pressure discharge lamp is inverted according to a magnitude relation between the detected voltage and the switch voltage, is changed in plural stages. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21)
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16. A projector, comprising:
- a discharge lamp lighting device;
a fan for air-cooling a high pressure discharge lamp; and
a projector control device which receives a lamp voltage detected by a discharge lamp lighting device and is capable of instructing, to the discharge lamp lighting device, an inversion frequency at which the polarity of the lamp current of the high pressure discharge lamp is inverted,wherein the projector control device sets a control condition for air-cooling by the fan according to the lamp voltage received from the high pressure discharge lamp and instructs, to the discharge lamp lighting device, an inversion frequency corresponding to the control condition.
- a discharge lamp lighting device;
Specification