Electroluminescent driving apparatus with photodetector
First Claim
1. An electroluminescent driving apparatus for causing an electroluminescent element to emit light by repeatedly applying an increased voltage to said electroluminescent element and releasing charges accumulated in said electroluminescent element by said increased voltage applied thereto, said apparatus comprising:
- voltage increasing means for generating said increased voltage to be applied to said electroluminescent element;
discharging means for releasing the charges accumulated in said electroluminescent element by said voltage increasing means;
control means for activating said discharging means when said increased voltage reaches a specified peak voltage; and
changing means having a photodetector element for sensing ambient brightness, said changing means changing said peak voltage for said control means based on an output from said photodetector element.
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Accused Products
Abstract
An EL driving apparatus is composed of a display portion, a photodiode as changing means for changing a reference voltage for controlling an increased voltage based on ambient brightness and a control portion for controlling the timing of discharging based on the reference voltage. The control portion has a comparator for comparing a specified peak value obtained by reducing the increased voltage generated by voltage increasing means with the reference voltage generated from within. The increased voltage is inputted to the control portion. The increased voltage is reduced to provide a detect voltage that can be inputted to the comparator. The comparator has a positive-phase input terminal for receiving the detect voltage and a negative-phase input terminal for receiving the reference voltage produced at a connection point between a constant current source and a resistor connected in series to each other. The photodiode is connected between the ground and the connection point between the constant current source and the resistor to form a reverse bias.
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Citations
10 Claims
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1. An electroluminescent driving apparatus for causing an electroluminescent element to emit light by repeatedly applying an increased voltage to said electroluminescent element and releasing charges accumulated in said electroluminescent element by said increased voltage applied thereto, said apparatus comprising:
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voltage increasing means for generating said increased voltage to be applied to said electroluminescent element; discharging means for releasing the charges accumulated in said electroluminescent element by said voltage increasing means; control means for activating said discharging means when said increased voltage reaches a specified peak voltage; and changing means having a photodetector element for sensing ambient brightness, said changing means changing said peak voltage for said control means based on an output from said photodetector element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification