US3879662A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential amplifier sliding reference
Assignee: United States Department of the Army
•
Filing: 1974-06-18
•
Granted: 1975-04-22
•
Expires: 1994-06-18
Abstract
Abstract A tolerance detector circuit comprising a differential amplifier circuit for comparing a signal to be measured with a reference voltage, a level sensor to indicate when the signal level differs from the desired values, and a means for allowing the reference voltage to slide or vary to achieve the desired in-tolerance range, while retaining the inherently high sensitivity of the differential amplifier.
Inventors
- 👤 Charles A Barneck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:40
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/165; G01R19/16566; G01R19/1659; G01R17/00; G01R17/02; H; H03; H03K; H03K3/00; H03K3/02; H03K3/023; H03K3/0233; H03K3/02337
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
167 words
A tolerance detector for indicating whether the voltage level of an input signal to be monitored lies within presettable upper and lower limits comprising a differential amplifier responding to said input signal and to a reference voltage and having a pair of output circuits, a voltage level sensing means having an input circuit coupled to said differential amplifier output circuits and having mutually exclusive high and low output voltage states, adjustable sliding reference voltage circuit means in circuit with said reference voltage input to the differential amplifier for clamping said reference voltage level to one of said presettable upper and lower limits only when the level of said input signal exceeds the corresponding upper or lower limit, one of said two differential amplifier output voltages exceeding a predetermined magnitude only during said clamping, said level sensing means attaining the low level output state in response to a differential amplifier output voltage exceeding said predetermined magnitude and attaining the high level output state during absence of said clamping.
Claim 2
Dependent Claim
167 words
A tolerance detector for indicating whether the voltage level of an input signal to be monitored lies within presettable upper and lower limits comprising a differential amplifier responding to said input signal and to a reference voltage and having a pair of output circuits, a voltage level sensing means having an input circuit coupled to said differential amplifier output circuits and having mutually exclusive high and low output voltage states, adjustable sliding reference voltage circuit means in circuit with said reference voltage input to the differential amplifier for clamping said reference voltage level to one of said presettable upper and lower limits only when the level of said input signal exceeds the corresponding upper or lower limit, one of said two differential amplifier output voltages exceeding a predetermined magnitude only during said clamping, said level sensing means attaining the low level output state in response to a differential amplifier output voltage exceeding said predetermined magnitude and attaining the high level output state during absence of said clamping.
Claim 3
Dependent Claim
167 words
A tolerance detector for indicating whether the voltage level of an input signal to be monitored lies within presettable upper and lower limits comprising a differential amplifier responding to said input signal and to a reference voltage and having a pair of output circuits, a voltage level sensing means having an input circuit coupled to said differential amplifier output circuits and having mutually exclusive high and low output voltage states, adjustable sliding reference voltage circuit means in circuit with said reference voltage input to the differential amplifier for clamping said reference voltage level to one of said presettable upper and lower limits only when the level of said input signal exceeds the corresponding upper or lower limit, one of said two differential amplifier output voltages exceeding a predetermined magnitude only during said clamping, said level sensing means attaining the low level output state in response to a differential amplifier output voltage exceeding said predetermined magnitude and attaining the high level output state during absence of said clamping.
Claim 4
Dependent Claim
167 words
A tolerance detector for indicating whether the voltage level of an input signal to be monitored lies within presettable upper and lower limits comprising a differential amplifier responding to said input signal and to a reference voltage and having a pair of output circuits, a voltage level sensing means having an input circuit coupled to said differential amplifier output circuits and having mutually exclusive high and low output voltage states, adjustable sliding reference voltage circuit means in circuit with said reference voltage input to the differential amplifier for clamping said reference voltage level to one of said presettable upper and lower limits only when the level of said input signal exceeds the corresponding upper or lower limit, one of said two differential amplifier output voltages exceeding a predetermined magnitude only during said clamping, said level sensing means attaining the low level output state in response to a differential amplifier output voltage exceeding said predetermined magnitude and attaining the high level output state during absence of said clamping.
Claim 5
Dependent Claim
43 words
A tolerance detector according to claim 1 wherein said input circuit of the level sensing means is coupled to the differential amplifier output circuits by way of diodes which are nonconducting when the level of said input signal lies within the aforesaid limits.
Claim 6
Dependent Claim
50 words
A tolerance detector according to claim 2 wherein said level sensing means is a transistor whose input electrode is at a voltage sufficient to bias the transistor into conduction when said diodes are nonconducting and at a voltage sufficient to cutoff the transistor when either of said diodes is conducting.
Claim 7
Dependent Claim
53 words
A tolerance detector according to claim 1 wherein said sliding reference voltage circuit means includes a high impedance voltage divider for establishing said reference voltage and permitting said reference voltage to follow closely changes in voltage level of said signal to be monitored while said signal voltage level lies within said presettable limits.
Claim 8
Dependent Claim
46 words
A tolerance detector according to claim 4 further including a first low impedance adjustable voltage divider for establishing a first voltage level equal to said upper limit, and a second adjustable low impedance voltage divider for establishing a second voltage level equal to said lower limit.
Claim 9
Dependent Claim
93 words
A tolerance detector according to claim 1 wherein said sliding reference voltage circuit means includes a first low impedance adjustable voltage divider for establishing a first voltage level equal to said upper limit, a first diode having an anode connected to said reference input circuit and a cathode connected to said first voltage and a second low impedance adjustable voltage divider for establishing a second voltage level equal to said lower limit and a second diode having a cathode connected to said reference input circuit and an anode connected to said second voltage.
Claim 10
Dependent Claim
27 words
A tolerance detector according to claim 6 wherein said first and second diodes are nonconducting when the level of said input signal lies within the aforesaid limits.
Claim 11
Dependent Claim
30 words
A tolerance detector according to claim 6 wherein said first and second diodes constitute clamping means for preventing variation of said reference voltage beyond said corresponding upper or lower limit.
References Cited (Backward Citations)
US3178698A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-21 | 1978-10-21 | 1979-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-21 | 1982-10-21 | 1983-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-21 | 1986-10-21 | 1987-04-22 | $7700.00 | Window Closed / Lapsed |