US4099073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Four-level voltage supply for liquid crystal display
Assignee: Sharp Corp
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Filing: 1976-08-26
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Granted: 1978-07-04
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Expires: 1996-08-26
Abstract
Abstract A power supply circuit supplies a liquid crystal energizing circuit with desired potentials for the purposes of energizing a liquid crystal display in accordance with combinations between first, second, third and reference potentials. The power supply circuit includes a first input terminal connected to a constant voltage source for supplying the first potential, a second input terminal connected to the reference potential, first, second, third, fourth and fifth output terminals for supplying the liquid crystal energizing circuit with desired potentials, impedance means connected between the first input terminal and the second input terminal for deriving the second potential and the third potential therefrom, means for always supplying the first output terminal and the fifth terminal with the first potential and the reference potential respectively, and switching means for determining whether the second, third and fourth output terminals are respectively with the first, second and third potentials or with the second, third and reference potentials. The last named switching means contain only P channel MOS transistors (or N channel MOS transistors).
Inventors
- 👤 Shintaro Hashimoto
- 👤 Yuuichi Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:45
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/04; G09G3/16; G09G3/18
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
170 words
A power supply circuit for supplying a liquid crystal display energizing circuit with desired potentials for the purposes of energizing a liquid crystal display in accordance with combinations between first, second, third and reference potentials, comprising: a first input terminal for supplying the first potential, connected to a constant voltage source; a second input terminal connected to the reference potential; first, second, third, fourth and fifth output terminals connected for supplying the liquid crystal display energizing circuit with desired potentials; impedance means connected between the first input terminal and the second input terminal for deriving the second potential and the third potential therefrom; means for always supplying the first output terminal and the fifth output terminal with the first potential and the reference potential, respectively; and switching means for controlling whether the second, third and fourth output terminals are respectively supplied with the first, second and third potentials or with the second, third and reference potentials; said switching means comprising field effect mode transistors of the same channel conductivity type.
Claim 2
Dependent Claim
170 words
A power supply circuit for supplying a liquid crystal display energizing circuit with desired potentials for the purposes of energizing a liquid crystal display in accordance with combinations between first, second, third and reference potentials, comprising: a first input terminal for supplying the first potential, connected to a constant voltage source; a second input terminal connected to the reference potential; first, second, third, fourth and fifth output terminals connected for supplying the liquid crystal display energizing circuit with desired potentials; impedance means connected between the first input terminal and the second input terminal for deriving the second potential and the third potential therefrom; means for always supplying the first output terminal and the fifth output terminal with the first potential and the reference potential, respectively; and switching means for controlling whether the second, third and fourth output terminals are respectively supplied with the first, second and third potentials or with the second, third and reference potentials; said switching means comprising field effect mode transistors of the same channel conductivity type.
Claim 3
Dependent Claim
23 words
A power supply circuit as set forth in claim 1 wherein the field effect mode transistors are of the P channel MOS type.
Claim 4
Dependent Claim
23 words
A power supply circuit as set forth in claim 1 wherein the field effect mode transistors are of the N channel MOS type.
Claim 5
Dependent Claim
22 words
A power supply circuit as set forth in claim 2 wherein said switching means comprises a pair of P channel MOS transistors.
Claim 6
Dependent Claim
59 words
A power supply circuit as set forth in claim 4 wherein one of the two P channel MOS transistors has a source-to-drain circuit connected between the first input terminal and the second output terminal and the other of the two P channel MOS transistors has a source-to-drain circuit connected between the second input terminal and the fourth output terminal.
Claim 7
Dependent Claim
34 words
A power supply circuit as set forth in claim 5 wherein impedance means are provided between the first input terminal and the source-to-drain circuit of said one of the two P channel MOS transistors.
Claim 8
Dependent Claim
30 words
A power supply circuit as set forth in claim 6 wherein an inverter circuit is provided and in circuit with the said one of the two P channel MOS transistors.
Claim 9
Dependent Claim
20 words
A power circuit as set forth in claim 7 wherein the inverter comprises a couple of P channel MOS transistors.
Claim 10
Dependent Claim
21 words
A power supply circuit as set forth in claim 8 wherein the P channel MOS transistors are of the enhancement/depletion type.
Claim 11
Dependent Claim
20 words
A power supply circuit as set forth in claim 1 wherein said switching means comprises a pair of bootstrap circuits.
Claim 12
Dependent Claim
23 words
A power supply circuit as set forth in claim 10 wherein each of said bootstrap circuits has a capacitor adapted to be biased.
Claim 13
Dependent Claim
30 words
A power supply circuit as set forth in claim 11 wherein each of said bootstrap circuits has a field effect mode transistor to control charging and discharging of said capacitor.
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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) | 1981-07-03 | 1982-01-02 | 1982-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-03 | 1986-01-02 | 1986-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-03 | 1990-01-02 | 1990-07-04 | $7700.00 | Window Closed / Lapsed |