Power supply for an electroluminescent display
First Claim
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1. An electroluminescent display system comprising an electroluminescent display and a power supply for the electroluminescent display, the power supply comprising:
- a fist input terminal and a second input terminal for supplying substantially direct current electrical energy;
a three terminal inductive unit having a first outer terminal and a second outer terminal and a center-tap, the first and second outer terminals also being output terminals for supplying power to the electroluminescent display, and the center-tap being connected to the first input terminal, the three terminal inductive unit and the electroluminescent display comprises an electrically resonant circuit having a natural resonant frequency;
a first controllable switching device and a second controllable switching device, each said switching device having a closed state and an open state, the first switching device being connected between the second input terminal and the first outer terminal and the second switching device being connected between the second input terminal and the second outer terminal; and
controlling means coupled to each of the switching devices for causing each of the switching devices to open and close alternately and in opposite phase to a state of the other switching device at a rate corresponding to an operating frequency that is approximately the natural resonant frequency of the resonant circuit, whereby a substantially sinusoidal supply of alternating current is supplied to the electroluminescent display.
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Abstract
Inductive power transfer across an extended gap (100) from a primary conductor (119) is provided by means of a resonant intermediate loop comprised of capacitor (118) with inductor (117) carrying a larger resonating current, that can in turn generate an inductive field to be collected by a pickup coil (120). This process and device find application in an electroluminescent advertising panel.
99 Citations
7 Claims
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1. An electroluminescent display system comprising an electroluminescent display and a power supply for the electroluminescent display, the power supply comprising:
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a fist input terminal and a second input terminal for supplying substantially direct current electrical energy;
a three terminal inductive unit having a first outer terminal and a second outer terminal and a center-tap, the first and second outer terminals also being output terminals for supplying power to the electroluminescent display, and the center-tap being connected to the first input terminal, the three terminal inductive unit and the electroluminescent display comprises an electrically resonant circuit having a natural resonant frequency;
a first controllable switching device and a second controllable switching device, each said switching device having a closed state and an open state, the first switching device being connected between the second input terminal and the first outer terminal and the second switching device being connected between the second input terminal and the second outer terminal; and
controlling means coupled to each of the switching devices for causing each of the switching devices to open and close alternately and in opposite phase to a state of the other switching device at a rate corresponding to an operating frequency that is approximately the natural resonant frequency of the resonant circuit, whereby a substantially sinusoidal supply of alternating current is supplied to the electroluminescent display. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification