US5212415A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Precharge circuit
Assignee: Toshiba Corp
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Filing: 1991-11-29
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Granted: 1993-05-18
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Expires: 2011-11-29
Abstract
Abstract A precharge circuit is provided with a step-up node circuit including a capacitor for delivering a drive voltage at a predetermined level to a load, and for raising the voltage level of the drive voltage so that it becomes equal to a value greater than the predetermined level by a specific value. This precharge circuit at least comprises a main P-channel MOS transistor for delivering the drive voltage at the predetermined level to the load through the step-up node circuit when a step-up input signal delivered to the step up node circuit is at a ground level, and a subsidiary P-channel MOS transistor for interrupting supply of the step-up input signal immediately before the drive voltage is raised to the predetermined level by the step-up input signal. Accordingly this precharge circuit normally operates immediately after being powered. Thus, initialization becomes unnecessary.
Inventors
- 👤 Kiyoharu Murakami
- 👤 Ryosuke Matsuo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:46
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/4063; G11C11/407; G11C11/409; G11C11/4094
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
271 words
A precharge circuit having step-up node means including a capacitor for supplying a drive voltage having a predetermined level, for raising said drive voltage to a stepped-up voltage level which is greater by a specific value than said predetermined level and for delivering said drive voltage at said predetermined level or at said stepped-up voltage level to a load, said precharge circuit comprising: main transistor means comprising a main P-channel metal oxide semiconductor (MOS) transistor having a gate terminal, a source terminal, a drain terminal and a substrate terminal; subsidiary transistor means comprising a subsidiary P-channel metal oxide semiconductor (MOS) transistor having a gate terminal, a source terminal, a drain terminal and a substrate terminal; means for connecting said drain terminal of said subsidiary transistor to said gate terminal of said main transistor; means for connecting said source terminal of said main transistor to a positive potential power supply; means for supplying a first input signal to said gate terminal of said subsidiary transistor; and means for supplying said drive voltage to said source and substrate terminals of said subsidiary transistor; said main transistor means providing said drive voltage at said predetermined level for delivery to said load through said step-up node means when a step-up input signal at ground level is input to said step-up node means; said subsidiary transistor means turning on, due to said drive voltage being raised by said step-up input signal, immediately before said drive voltage exceeds said predetermined value and turning off due to said gate of said subsidiary transistor being input with a voltage level which is the same level as said drive voltage.
Claim 2
Dependent Claim
271 words
A precharge circuit having step-up node means including a capacitor for supplying a drive voltage having a predetermined level, for raising said drive voltage to a stepped-up voltage level which is greater by a specific value than said predetermined level and for delivering said drive voltage at said predetermined level or at said stepped-up voltage level to a load, said precharge circuit comprising: main transistor means comprising a main P-channel metal oxide semiconductor (MOS) transistor having a gate terminal, a source terminal, a drain terminal and a substrate terminal; subsidiary transistor means comprising a subsidiary P-channel metal oxide semiconductor (MOS) transistor having a gate terminal, a source terminal, a drain terminal and a substrate terminal; means for connecting said drain terminal of said subsidiary transistor to said gate terminal of said main transistor; means for connecting said source terminal of said main transistor to a positive potential power supply; means for supplying a first input signal to said gate terminal of said subsidiary transistor; and means for supplying said drive voltage to said source and substrate terminals of said subsidiary transistor; said main transistor means providing said drive voltage at said predetermined level for delivery to said load through said step-up node means when a step-up input signal at ground level is input to said step-up node means; said subsidiary transistor means turning on, due to said drive voltage being raised by said step-up input signal, immediately before said drive voltage exceeds said predetermined value and turning off due to said gate of said subsidiary transistor being input with a voltage level which is the same level as said drive voltage.
Claim 3
Dependent Claim
52 words
A precharge circuit as set forth in claim 1, which further comprises an N-channel MOS transistor having a gate terminal supplied with said first input signal, a source terminal to which a ground power supply is connected, and a drain terminal to which said drain terminal of said subsidiary transistor is connected.
Claim 4
Dependent Claim
37 words
A precharge circuit as set forth in claim 2, wherein said capacitor comprises an N-channel MOS capacitor having a first terminal supplied with said step-up input signal, and a second terminal at which said drive voltage appears.
Claim 5
Dependent Claim
57 words
A precharge circuit as set forth in claim 3, wherein when said step-up input signal is at a ground level, said first input signal serves as a positive potential supply source, and immediately before said step-up input signal rises up to a positive potential supply source level, said first input signal falls down to said ground level.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-05-17 | 1996-11-16 | 1997-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-17 | 2000-11-16 | 2001-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-17 | 2004-11-16 | 2005-05-18 | $7700.00 | Window Closed / Lapsed |