← Back to Patent Explorer
US5264741A Expired / Lapsed US ⏱️ 0.0 years remaining

Low current, fast, CMOS static pullup circuit for static random-access memories

Assignee: Mentor Graphics Corp
•
Filing: 1992-06-19
•
Granted: 1993-11-23
•
Expires: 2012-06-19
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A pullup circuit for use with plurality of N-Channel pulldown transistors connected to a bit line includes a P-channel MOS pullup transistor connected between the bit line and a voltage rail. An inverter is connected between the bit line and the drain of an N-Channel MOS transistor having its gate connected to the voltage rail and its source connected to the gate of the P-Channel MOS pullup transistor. A first P-Channel MOS transistor is connected between the voltage rail and the gate of the P-Channel MOS pullup transistor. A second P-Channel MOS transistor having its gate connected to ground is connected between the bit line and the gate of the first P-Channel MOS transistor. Four P-Channel MOS divider transistors are connected between the drain of the first P-Channel MOS transistor and ground. The gates of the P-Channel MOS divider transistors are connected together to ground. The P-Channel MOS pullup transistor and the N-Channel MOS pulldown transistors are large. The first and second P-Channel MOS transistors, the first N-Channel MOS transistor, and the P-Channel MOS divider transistors are close to minimum size. The P-Channel and N-Channel devices comprising the inverter devices are larger than minimum size.

Inventors

  • 👤 Adi Srinivasan
  • 👤 Ta-Pen Guo

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-07 19:15
CPC Classifications
H; H03; H03K; H03K19/00; H03K19/01; H03K19/017; H03K19/01707; H03K19/01721

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 216 words
A pullup circuit for use with at least one N-Channel pulldown transistor connected to a bit line comprising: a P-Channel MOS pullup transistor having a source connected to a voltage rail a drain connected to said bit line, and a gate; a N-Channel MOS transistor having a gate connected to said voltage rail, a source connected to the gate of the P-Channel MOS pullup transistor, and a drain; an inverter connected between said bit line and said drain of said N-Channel MOS transistor; a first P-Channel MOS transistor connected between said voltage rail and said gate of said P-Channel MOS pullup transistor; a second P-Channel MOS transistor having a gate connected to ground, a drain connected to said bit line and a source connected to said gate of said first P-Channel MOS transistor; four P-Channel MOS divider transistors connected in series between said drain of said first P-Channel MOS transistor and ground, said four P-Channel MOS divider transistors having gates connected together to ground; wherein said P-Channel MOS pullup transistor and said at least one N-Channel MOS pulldown transistor are large, said first and second P-Channel MOS transistors, said first N-Channel MOS transistor, and said P-Channel MOS divider transistors are about minimum size, and said inverter comprises series-connected P-Channel and N-Channel devices larger than minimum size.
Claim 2
Dependent Claim 216 words
A pullup circuit for use with at least one N-Channel pulldown transistor connected to a bit line comprising: a P-Channel MOS pullup transistor having a source connected to a voltage rail a drain connected to said bit line, and a gate; a N-Channel MOS transistor having a gate connected to said voltage rail, a source connected to the gate of the P-Channel MOS pullup transistor, and a drain; an inverter connected between said bit line and said drain of said N-Channel MOS transistor; a first P-Channel MOS transistor connected between said voltage rail and said gate of said P-Channel MOS pullup transistor; a second P-Channel MOS transistor having a gate connected to ground, a drain connected to said bit line and a source connected to said gate of said first P-Channel MOS transistor; four P-Channel MOS divider transistors connected in series between said drain of said first P-Channel MOS transistor and ground, said four P-Channel MOS divider transistors having gates connected together to ground; wherein said P-Channel MOS pullup transistor and said at least one N-Channel MOS pulldown transistor are large, said first and second P-Channel MOS transistors, said first N-Channel MOS transistor, and said P-Channel MOS divider transistors are about minimum size, and said inverter comprises series-connected P-Channel and N-Channel devices larger than minimum size.

References Cited (Backward Citations)

US4750155A Cited
US5148390A Cited
US4771284A Cited
US5056062A Cited
US4918341A Cited
US5020028A Cited
US5041746A Cited
US5191555A Cited
US5109167A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1996-11-22 1997-05-24 1997-11-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2000-11-22 2001-05-24 2001-11-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2004-11-22 2005-05-24 2005-11-23 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag