Patent US2721944A successfully refreshed from Google Patents.
← Back to Patent Explorer
US5493203A Expired / Lapsed US ⏱️ 0.0 years remaining

Low quiescent current voltage regulator

Assignee: Hewlett Packard Development Co LP
•
Filing: 1995-01-19
•
Granted: 1996-02-20
•
Expires: 2015-01-19
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A low quiescent current voltage regulator particularly suited for providing current to the RTC/CMOS memory section of a notebook computer. The gate of the JFET is grounded, the drain connected to the main battery and the source connected to the RTC voltage input of the RTC/CMOS memory section. The JFET source voltage approaches the gate-source cutoff voltage of the JFET. This cutoff voltage is selected to be in the proper range for the RTC/CMOS memory section. A complete RTC voltage control circuit is configured to provide 5 volts from the system voltage when the computer is turned on, 3 to 5 volts from the JFET when the computer is turned off and the main battery is present and 3 volts from the RTC battery when the computer is turned off and the main battery is removed.

Inventors

  • 👤 Scott W. Dalton

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 15:07
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/40; G05F1/44; G05F1/445

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 100 words
A low quiescent current voltage regulator circuit comprising: a high voltage source providing a positive voltage and ground; a ground connected load designed to operate at a voltage below the level of the positive voltage of said high voltage source and having a small current draw; and a junction field effect transistor having its gate connected to ground, its drain connected to the positive voltage provided by said high voltage source and its source connected to said load, wherein the gate to source cut off voltage of the junction field effect transistor is approximately the operating voltage of said load.
Claim 2
Dependent Claim 100 words
A low quiescent current voltage regulator circuit comprising: a high voltage source providing a positive voltage and ground; a ground connected load designed to operate at a voltage below the level of the positive voltage of said high voltage source and having a small current draw; and a junction field effect transistor having its gate connected to ground, its drain connected to the positive voltage provided by said high voltage source and its source connected to said load, wherein the gate to source cut off voltage of the junction field effect transistor is approximately the operating voltage of said load.
Claim 3
Dependent Claim 211 words
A circuit for providing a voltage to a continuous, low current load in a notebook computer, the notebook computer including a removable battery providing ground and a high positive voltage and a power supply circuit for providing a computer operating voltage developed from the high positive voltage provided by the removable battery and capable of being turned on or off to turn the computer on or off, the load utilizing a voltage less than the positive voltage provided directly by the battery, the circuit comprising: means connected to the load and to the power supply circuit for providing the computer operating voltage to the load when the computer is turned on; and a low quiescent current voltage regulator connected to the high positive voltage of the removable battery and the load for providing a voltage utilized by the load when the computer is turned off and the removable battery is present, wherein said low quiescent current voltage regulator comprises a junction field effect transistor having its gate connected to ground, its drain connected to the high positive voltage of the removable battery and its source connected to the load, and wherein the gate to source cutoff voltage of said junction field effect transistor is approximately the voltage utilized by the load.
Claim 4
Dependent Claim 211 words
A circuit for providing a voltage to a continuous, low current load in a notebook computer, the notebook computer including a removable battery providing ground and a high positive voltage and a power supply circuit for providing a computer operating voltage developed from the high positive voltage provided by the removable battery and capable of being turned on or off to turn the computer on or off, the load utilizing a voltage less than the positive voltage provided directly by the battery, the circuit comprising: means connected to the load and to the power supply circuit for providing the computer operating voltage to the load when the computer is turned on; and a low quiescent current voltage regulator connected to the high positive voltage of the removable battery and the load for providing a voltage utilized by the load when the computer is turned off and the removable battery is present, wherein said low quiescent current voltage regulator comprises a junction field effect transistor having its gate connected to ground, its drain connected to the high positive voltage of the removable battery and its source connected to the load, and wherein the gate to source cutoff voltage of said junction field effect transistor is approximately the voltage utilized by the load.
Claim 5
Dependent Claim 35 words
The circuit of claim 2, further comprising: a low energy battery connected to the load for providing a voltage utilized by the load when the computer is turned off and the removable battery is removed.
Claim 6
Dependent Claim 63 words
The circuit of claim 2, wherein said means for providing the computer operating voltage includes: a PNP transistor having its emitter connected to the computer operating voltage and its collector coupled to the load; and an NPN transistor having its emitter connected to ground, its base coupled to the computer operating voltage and its collector coupled to the base of said PNP transistor.
Claim 7
Dependent Claim 80 words
The circuit of claim 4, further comprising: a battery transistor connected between the negative terminal of said low energy battery and ground and to the collector of said NPN transistor so that said battery transistor connects said low energy battery to ground when said NPN transistor is off and disconnects said low energy battery from ground when said NPN transistor is on; and wherein said low energy battery has its positive terminal coupled to the collector of said PNP transistor.
Claim 8
Dependent Claim 63 words
The circuit of claim 2, wherein said means for providing the computer operating voltage includes: a PNP transistor having its emitter connected to the computer operating voltage and its collector coupled to the load; and an NPN transistor having its emitter connected to ground, its base coupled to the computer operating voltage and its collector coupled to the base of said PNP transistor.

References Cited (Backward Citations)

US4319179A Cited
US4733159A Cited
US4906913A Cited
US5023543A Cited
US5105144A Cited
US5164542A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1999-02-19 1999-08-21 2000-02-20 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2003-02-19 2003-08-21 2004-02-20 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2007-02-19 2007-08-21 2008-02-20 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag