Thin-film electroluminescent display power supply system for providing regulated write voltages
First Claim
1. A power supply for a thin-film electroluminescent display system having an electroluminescent display panel that, in response to the application of a panel display voltage which is above a panel threshold voltage, emits a quantity of light, comprising;
- a power converter having an input for receiving a selectively applied first reference voltage for converting said reference voltage to a panel write voltage, and having an output from which the panel write voltage is applied to the display panel so as to at least partially establish the panel display voltage;
a feedback link having a first end connected to said power converter output for receiving said panel write voltage and having a second end;
a divider circuit having a selected resistance connected to said feedback link for producing a feedback signal on said feedback link second end that is a function of the panel write voltage and said divider circuit resistance, wherein said divider circuit resistance is a function of the panel threshold voltage;
an error comparator connected to said feedback link second end for receiving said feedback signal and a second reference voltage and, in response thereto, generating an error signal; and
a voltage regulator connected to receive said first reference voltage and connected to said error comparator for receiving said error signal for selectively applying said first reference voltage to said power converter in response to said error signal so as to control development of the panel write voltage.
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Accused Products
Abstract
A power supply system for controlling the drive voltages applied to a thin film electroluminescent (TFEL) display panel is disclosed. The system includes a power supply that generates the drive voltages to the TFEL display panel and causes it to emit light. A replaceable or resettable display voltage memory located adjacent the display panel provides the power supply with voltage information specific to the display panel. A feedback circuit measures the light emitted from the display panel. A balancing circuit controls multiple display voltages so that they have the proper relationship with respect to each other. The information from the display voltage memory and the feedback circuit is used by the power supply to control the output of the display voltages.
116 Citations
28 Claims
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1. A power supply for a thin-film electroluminescent display system having an electroluminescent display panel that, in response to the application of a panel display voltage which is above a panel threshold voltage, emits a quantity of light, comprising;
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a power converter having an input for receiving a selectively applied first reference voltage for converting said reference voltage to a panel write voltage, and having an output from which the panel write voltage is applied to the display panel so as to at least partially establish the panel display voltage; a feedback link having a first end connected to said power converter output for receiving said panel write voltage and having a second end; a divider circuit having a selected resistance connected to said feedback link for producing a feedback signal on said feedback link second end that is a function of the panel write voltage and said divider circuit resistance, wherein said divider circuit resistance is a function of the panel threshold voltage; an error comparator connected to said feedback link second end for receiving said feedback signal and a second reference voltage and, in response thereto, generating an error signal; and a voltage regulator connected to receive said first reference voltage and connected to said error comparator for receiving said error signal for selectively applying said first reference voltage to said power converter in response to said error signal so as to control development of the panel write voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A power supply for an electroluminescent display system having an electroluminescent display panel that, in response to the application of a panel display voltage, emits a quantity of light that is a function of the panel display voltage, and to which a modulation voltage is supplied, comprising:
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a transformer having primary and secondary windings wherein a first reference voltage is applied to said transformer primary winding and wherein positive and negative write voltages are developed across said transformer secondary for application to the electroluminescent display panel to establish the panel display voltage in combination with the modulation voltage and wherein said transformer secondary winding has a center tap; and a balancing circuit connected to said transformer secondary winding for receiving said positive and negative write voltages and connected to receive a reference voltage and, in response thereto, generating an offset voltage applied to said transformer secondary winding center tap so that said positive and negative write voltages are maintained at a fixed relationship relative to at least a portion of the modulation voltage. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification