Lighting control circuit for vehicle lighting equipment
First Claim
1. A lighting control circuit for vehicle lighting equipment, comprising:
- selecting means for selecting a higher voltage from a battery voltage of a vehicle or a control voltage used to control a semiconductor light source;
controlling means for controlling a supply of current to the semiconductor light source in response to the control voltage, while using the voltage selected by the selecting means as an energy; and
deciding means for deciding whether the control voltage corresponds to a voltage used to turn on the semiconductor light source in a dimmed lighting mode;
wherein the controlling means reduces the supply of current to the semiconductor light source rather than a full lighting mode when an affirmative decision result is output from the deciding means.
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Accused Products
Abstract
A higher voltage out of a battery voltage applied to an ignition voltage terminal or a control voltage applied to a control voltage terminal is supplied to a switching regulator via a diode. Then, a supply of current to an LED in the switching regulator is controlled in compliance with the control voltage while using an input voltage as energy. When a PWM signal is input into a control voltage terminal as the control voltage, transistors are turned off and on, whereby an instruction to turn-on the-LED in a dimmed lighting mode is issued to the switching regulator. Then, a current that is smaller than that supplied in a full lighting mode is supplied to the LED.
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Citations
6 Claims
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1. A lighting control circuit for vehicle lighting equipment, comprising:
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selecting means for selecting a higher voltage from a battery voltage of a vehicle or a control voltage used to control a semiconductor light source;
controlling means for controlling a supply of current to the semiconductor light source in response to the control voltage, while using the voltage selected by the selecting means as an energy; and
deciding means for deciding whether the control voltage corresponds to a voltage used to turn on the semiconductor light source in a dimmed lighting mode;
wherein the controlling means reduces the supply of current to the semiconductor light source rather than a full lighting mode when an affirmative decision result is output from the deciding means. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification