US5440208A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Driver circuit for electroluminescent panel
Assignee: Motorola Mobility LLC
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Filing: 1993-10-29
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Granted: 1995-08-08
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Expires: 2013-10-29
Abstract
Abstract An electronic device (100) is disclosed including an electroluminescent (EL) backlight panel (140) and an EL driver circuit (210). The EL driver circuit (210) provides power to the EL backlight (140), as well as panel aging compensation and user adjustment capabilities. The EL driver circuit (210) is low-cost, small-size, and designed in such a way to be easily integrated into a custom integrated circuit. A method is provided for controlling and converting power to the EL backlight panel (140).
Inventors
- 👤 Robert G. Uskali
- 👤 David B. Bell
- 👤 Wilson D. Pace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:44
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/3406; H; H05; H05B; H05B44/00; G09G2320/00; G09G2320/04; G09G2320/043; G09G2320/06; G09G2320/0606; G09G2320/0626; G09G2330/00; G09G2330/02; Y; Y02; Y02B; Y02B20/00; Y02B20/30; Y10; Y10S; Y10S315/00; Y10S315/04
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
215 words
A driver circuit for converting and controlling power to an electroluminescent panel, comprising: a pulse-width modulation circuit for providing a modulated pulse train, said pulse-width modulation circuit further including an enable input and a regulating means for adjusting a pulse width, a panel drive frequency generator, electrically coupled to said pulse-width modulation circuit, for providing a panel drive frequency, and for providing a signal to said enable input for disabling said modulated pulse train, a means for storing magnetic energy, electrically coupled to a power source, a first switching means, electrically coupled to said means for storing magnetic energy and responsive to said pulse train, for controlling said storing magnetic energy, a second switching means, electrically coupled to said first switching means, said means for storing magnetic energy and said electroluminescent panel, for transferring energy from said means for storing magnetic energy to said electroluminescent panel, a resistor, electrically coupled to said electroluminescent panel, for setting an electroluminescent panel discharge time constant, a third switching means electrically coupled to said resistor and responsive to said panel drive frequency generator for draining energy from said electroluminescent panel through said resistor, and feedback means, coupled to said pulse-width modulation circuit and responsive to said panel drive frequency, for resetting the initial state of said pulse-width modulation circuit.
Claim 2
Dependent Claim
215 words
A driver circuit for converting and controlling power to an electroluminescent panel, comprising: a pulse-width modulation circuit for providing a modulated pulse train, said pulse-width modulation circuit further including an enable input and a regulating means for adjusting a pulse width, a panel drive frequency generator, electrically coupled to said pulse-width modulation circuit, for providing a panel drive frequency, and for providing a signal to said enable input for disabling said modulated pulse train, a means for storing magnetic energy, electrically coupled to a power source, a first switching means, electrically coupled to said means for storing magnetic energy and responsive to said pulse train, for controlling said storing magnetic energy, a second switching means, electrically coupled to said first switching means, said means for storing magnetic energy and said electroluminescent panel, for transferring energy from said means for storing magnetic energy to said electroluminescent panel, a resistor, electrically coupled to said electroluminescent panel, for setting an electroluminescent panel discharge time constant, a third switching means electrically coupled to said resistor and responsive to said panel drive frequency generator for draining energy from said electroluminescent panel through said resistor, and feedback means, coupled to said pulse-width modulation circuit and responsive to said panel drive frequency, for resetting the initial state of said pulse-width modulation circuit.
Claim 3
Dependent Claim
46 words
The driver circuit recited in claim 1, wherein said regulating means further includes: a voltage source for providing a reference voltage to said pulse-width modulation circuit; and a variable resistor coupled to said voltage source for adjusting an input voltage to said pulse width modulation circuit.
Claim 4
Dependent Claim
28 words
The driver circuit recited in claim 1, wherein said regulating means further includes: a variable voltage source coupled to a computer controlled digital-to-analog converter for controlling panel brightness.
Claim 5
Dependent Claim
27 words
The driver circuit recited in claim 1, further comprising: a second resistor electrically connected in series with said electroluminescent panel for regulating energy to said electroluminescent panel.
Claim 6
Dependent Claim
15 words
The driver circuit recited in claim 1, wherein said second switching means includes a diode.
Claim 7
Dependent Claim
15 words
The driver circuit recited in claim 5, wherein said first switching means includes a transistor.
Claim 8
Dependent Claim
15 words
The driver circuit recited in claim 6, wherein said third switching means includes a transistor.
Claim 9
Dependent Claim
17 words
The driver circuit recited in claim 1, wherein said panel drive frequency is derived from an oscillator.
Claim 10
Dependent Claim
14 words
The driver circuit recited in claim 1, wherein said feedback means includes a resistor.
Claim 11
Dependent Claim
15 words
The driver circuit recited in claim 9, wherein said feedback means further includes a diode.
Claim 12
Dependent Claim
17 words
The driver circuit recited in claim 1, wherein said means for storing magnetic energy includes a transformer.
Claim 13
Dependent Claim
17 words
The driver circuit recited in claim 1, wherein said means for storing magnetic energy includes an inductor.
Claim 14
Dependent Claim
230 words
An electronic device having an electroluminescent display panel, comprising: a computer having a processor, a memory, a power supply, and an operator interface comprising said electroluminescent display panel, a pulse-width modulation circuit for providing a modulated pulse train, said pulse-width modulation circuit further including an enable input and a regulating means for adjusting a pulse width, a panel drive frequency generator, electrically coupled to said pulse-width modulation circuit, for providing a panel drive frequency, and for providing a signal to said enable input for disabling said modulated pulse train, a means for storing magnetic energy, electrically coupled to said power supply, a first switching means, electrically coupled to said means for storing magnetic energy and responsive to said pulse train, for controlling said storing magnetic energy, a second switching means, electrically coupled to said first switching means, said means for storing magnetic energy and said electroluminescent panel, for transferring energy from said means for storing magnetic energy to said electroluminescent panel, a resistor, electrically coupled to said electroluminescent panel, for setting an electroluminescent panel discharge time constant, a third switching means electrically coupled to said resistor and responsive to said panel drive frequency generator for draining energy from said electroluminescent panel through said resistor, and feedback means, coupled to said pulse-width modulation circuit and responsive to said panel drive frequency, for resetting the initial state of said pulse-width modulation circuit.
Claim 15
Dependent Claim
230 words
An electronic device having an electroluminescent display panel, comprising: a computer having a processor, a memory, a power supply, and an operator interface comprising said electroluminescent display panel, a pulse-width modulation circuit for providing a modulated pulse train, said pulse-width modulation circuit further including an enable input and a regulating means for adjusting a pulse width, a panel drive frequency generator, electrically coupled to said pulse-width modulation circuit, for providing a panel drive frequency, and for providing a signal to said enable input for disabling said modulated pulse train, a means for storing magnetic energy, electrically coupled to said power supply, a first switching means, electrically coupled to said means for storing magnetic energy and responsive to said pulse train, for controlling said storing magnetic energy, a second switching means, electrically coupled to said first switching means, said means for storing magnetic energy and said electroluminescent panel, for transferring energy from said means for storing magnetic energy to said electroluminescent panel, a resistor, electrically coupled to said electroluminescent panel, for setting an electroluminescent panel discharge time constant, a third switching means electrically coupled to said resistor and responsive to said panel drive frequency generator for draining energy from said electroluminescent panel through said resistor, and feedback means, coupled to said pulse-width modulation circuit and responsive to said panel drive frequency, for resetting the initial state of said pulse-width modulation circuit.
Claim 16
Dependent Claim
45 words
The driver circuit recited in claim 13, wherein said regulating means further includes: a voltage source for providing a reference voltage to said pulse-width modulation circuit; and a variable resistor coupled to said voltage source for adjusting an input voltage to said pulse-width modulation circuit.
Claim 17
Dependent Claim
27 words
The driver circuit recited in claim 13, further including: a second resistor electrically connected in series with said electroluminescent panel for regulating energy to said electroluminescent panel.
Claim 18
Dependent Claim
15 words
The driver circuit recited in claim 13, wherein said second switching means includes a diode.
Claim 19
Dependent Claim
15 words
The driver circuit recited in claim 16, wherein said first switching means includes a transistor.
Claim 20
Dependent Claim
15 words
The driver circuit recited in claim 17, wherein said third switching means includes a transistor.
Claim 21
Dependent Claim
19 words
The driver circuit recited in claim 13, wherein said panel drive frequency is derived from said pulse-width modulation circuit.
Claim 22
Dependent Claim
14 words
The driver circuit recited in claim 13, wherein said feedback means includes a resistor.
Claim 23
Dependent Claim
15 words
The driver circuit recited in claim 20, wherein said feedback means further includes a diode.
Claim 24
Dependent Claim
17 words
The driver circuit recited in claim 13, wherein said means for storing magnetic energy includes a transformer.
Claim 25
Dependent Claim
17 words
The driver circuit recited in claim 13, wherein said means for storing magnetic energy includes an inductor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-08-07 | 1999-02-06 | 1999-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-07 | 2003-02-06 | 2003-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-07 | 2007-02-06 | 2007-08-08 | $7700.00 | Window Closed / Lapsed |