Discharge centering lamp lighting device
First Claim
1. A discharge lamp lighting device which turns on a discharge lamp by an arc discharge, comprising:
- a power supply circuit which supplies power to the discharge lamp;
an inverter which is provided in a downstream side of the power supply circuit and inverts polarity of a voltage to be applied to the discharge lamp;
a coil which is provided between the power supply circuit and the inverter; and
a series connection circuit of a capacitor and a switching element which is connected in parallel to power input side nodes of the inverter,wherein the switching element is controlled to be turned on after discharge state of the discharge lamp is changed to an arc discharge, andwhen the inverter performs polarity inversion, a dead time period is controlled so as to be 2 μ
s or shorter at least in a normal lighting operation of the discharge lamp.
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Accused Products
Abstract
A discharge lamp lighting device can reduce a variation in luminous flux at the time when the polarity of a voltage to be applied to the discharge lamp is inverted, prevent an excessively large amount of current from flowing through the discharge lamp at the time of starting, prevent the fade-out of discharge when the discharge mode returns from an arc discharge mode to a glow discharge mode, and reduce the ripple of a lamp current in a normal lighting mode. A coil is provided in an output current path of a power supply circuit comprising, for example, a step-down chopper, and a smoothing capacitor is provided in the next stage of the coil so that it selectively is turned on or off by a switching element. An inverter comprising, for example, a full bridge is provided in the next stage of the smoothing capacitor.
19 Citations
12 Claims
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1. A discharge lamp lighting device which turns on a discharge lamp by an arc discharge, comprising:
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a power supply circuit which supplies power to the discharge lamp; an inverter which is provided in a downstream side of the power supply circuit and inverts polarity of a voltage to be applied to the discharge lamp; a coil which is provided between the power supply circuit and the inverter; and a series connection circuit of a capacitor and a switching element which is connected in parallel to power input side nodes of the inverter, wherein the switching element is controlled to be turned on after discharge state of the discharge lamp is changed to an arc discharge, and when the inverter performs polarity inversion, a dead time period is controlled so as to be 2 μ
s or shorter at least in a normal lighting operation of the discharge lamp. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification