US3870965A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current mode operational amplifier
Assignee: Motorola Solutions Inc
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Filing: 1973-01-08
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Granted: 1975-03-11
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Expires: 1993-01-08
Abstract
Abstract A current mode operational amplifier is shown which is powered by a single voltage supply and operates in response to input signals represented by current values. The input system for the operational amplifier employs an inverting input circuit responsive to a first input signal and a non-inverting input circuit responsive to a second input signal. A current mirror circuit is employed for subtracting one input signal from the second input signal and the difference signal is applied to the operational amplifier.
Inventors
- 👤 Thomas M Frederiksen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:37
CPC Classifications
H; H03; H03K; H03K19/00; H03K19/02; H03K19/08; H03K19/082; H03K19/09; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/22; G05F3/222; G05F3/227; G06; G06G; G06G7/00; G06G7/12; G06G7/14; H03F; H03F1/00; H03F1/30; H03F1/302; H03F1/307; H03F3/00; H03F3/30; H03F3/3083; H03F3/34; H03F3/343; H03F3/347; H03K3/00; H03K3/02; H03K3/023; H03K9/00; H03K9/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
222 words
A circuit for generating a difference current value between a pair of current mode input signals comprising: a first transistor having emitter, collector and base electrodes and said collector electrode being connected to a first source of potential and said emitter electrode being connected to a second source of potential different from said first source of potential; first input means for supplying a current equivalent of a first input signal to said base electrode of said first transistor; a second transistor having emitter, collector and base electrodes and said collector electrode being coupled with said base electrode of said first transistor and said emitter electrode being coupled with said second source of potential; a diode matched to said second transistor connected between said base electrode and said second source of potential and poled to conduct current in the same direction as the base-emitter junction of said second transistor for developing a predetermined driving voltage for said second transistor; and second input means for supplying a current equivalent of a second input signal to said base electrode of said second transistor whereby, said second transistor under the influence of said predetermined driving voltage pulls current from said base electrode of said first transistor equal to the value of said second input signal for subtracting said second input signal from said first input signal.
Claim 2
Dependent Claim
222 words
A circuit for generating a difference current value between a pair of current mode input signals comprising: a first transistor having emitter, collector and base electrodes and said collector electrode being connected to a first source of potential and said emitter electrode being connected to a second source of potential different from said first source of potential; first input means for supplying a current equivalent of a first input signal to said base electrode of said first transistor; a second transistor having emitter, collector and base electrodes and said collector electrode being coupled with said base electrode of said first transistor and said emitter electrode being coupled with said second source of potential; a diode matched to said second transistor connected between said base electrode and said second source of potential and poled to conduct current in the same direction as the base-emitter junction of said second transistor for developing a predetermined driving voltage for said second transistor; and second input means for supplying a current equivalent of a second input signal to said base electrode of said second transistor whereby, said second transistor under the influence of said predetermined driving voltage pulls current from said base electrode of said first transistor equal to the value of said second input signal for subtracting said second input signal from said first input signal.
Claim 3
Dependent Claim
222 words
A circuit for generating a difference current value between a pair of current mode input signals comprising: a first transistor having emitter, collector and base electrodes and said collector electrode being connected to a first source of potential and said emitter electrode being connected to a second source of potential different from said first source of potential; first input means for supplying a current equivalent of a first input signal to said base electrode of said first transistor; a second transistor having emitter, collector and base electrodes and said collector electrode being coupled with said base electrode of said first transistor and said emitter electrode being coupled with said second source of potential; a diode matched to said second transistor connected between said base electrode and said second source of potential and poled to conduct current in the same direction as the base-emitter junction of said second transistor for developing a predetermined driving voltage for said second transistor; and second input means for supplying a current equivalent of a second input signal to said base electrode of said second transistor whereby, said second transistor under the influence of said predetermined driving voltage pulls current from said base electrode of said first transistor equal to the value of said second input signal for subtracting said second input signal from said first input signal.
Claim 4
Dependent Claim
222 words
A circuit for generating a difference current value between a pair of current mode input signals comprising: a first transistor having emitter, collector and base electrodes and said collector electrode being connected to a first source of potential and said emitter electrode being connected to a second source of potential different from said first source of potential; first input means for supplying a current equivalent of a first input signal to said base electrode of said first transistor; a second transistor having emitter, collector and base electrodes and said collector electrode being coupled with said base electrode of said first transistor and said emitter electrode being coupled with said second source of potential; a diode matched to said second transistor connected between said base electrode and said second source of potential and poled to conduct current in the same direction as the base-emitter junction of said second transistor for developing a predetermined driving voltage for said second transistor; and second input means for supplying a current equivalent of a second input signal to said base electrode of said second transistor whereby, said second transistor under the influence of said predetermined driving voltage pulls current from said base electrode of said first transistor equal to the value of said second input signal for subtracting said second input signal from said first input signal.
Claim 5
Dependent Claim
230 words
In combination: an operational amplifier operating in response to a single power supply and including as its input stage a first transistor of a predetermined conductivity type having emitter, collector and base electrodes and said collector electrode being connected to a source of positive potential and said emitter electrode being connected to a source of more negative potential; first input means for supplying a current equivalent of a first input signal to said base electrode of said first transistor; a second transistor of said predetermined conductivity type having emitter, collector and base electrodes and said collector electrode being connected to said base electrode of said first transistor and said emitter electrode being connected to a source of more negative potential; a diode matched to said second transistor connected between said base electrode and said source of more negative potential and poled to conduct current in the same direction as the base-emitter junction of said second transistor for developing a predetermined driving voltage for said second transistor; and second input means for supplying a current equivalent of a second input signal to said base electrode of said second transistor whereby, said second transistor under the influence of said predetermined driving voltage pulls current from said base electrode of said first transistor equal to the value of said second input signal for subtracting said second input signal from said first input signal.
Claim 6
Dependent Claim
230 words
In combination: an operational amplifier operating in response to a single power supply and including as its input stage a first transistor of a predetermined conductivity type having emitter, collector and base electrodes and said collector electrode being connected to a source of positive potential and said emitter electrode being connected to a source of more negative potential; first input means for supplying a current equivalent of a first input signal to said base electrode of said first transistor; a second transistor of said predetermined conductivity type having emitter, collector and base electrodes and said collector electrode being connected to said base electrode of said first transistor and said emitter electrode being connected to a source of more negative potential; a diode matched to said second transistor connected between said base electrode and said source of more negative potential and poled to conduct current in the same direction as the base-emitter junction of said second transistor for developing a predetermined driving voltage for said second transistor; and second input means for supplying a current equivalent of a second input signal to said base electrode of said second transistor whereby, said second transistor under the influence of said predetermined driving voltage pulls current from said base electrode of said first transistor equal to the value of said second input signal for subtracting said second input signal from said first input signal.
Claim 7
Dependent Claim
92 words
The combination as recited in claim 2, wherein the source of more negative potential is ground potential, said operational amplifier has an output terminal coupled with the collector of said first transistor, and further including: a single power supply coupled with the source of positive potential; a feedback resistor being connected between said output terminal and said first input means; a bias resistor being connected between said seCond input means and said single power supply and being related to said feedback resistor such as to fix the output quiescent voltage operating level.
Claim 8
Dependent Claim
56 words
The combination as recited in claim 2, wherein said operational amplifier has an output terminal coupled with the collector of said first transistor and further including: a feedback circuit connected between said output terminal and said first input means; and a first current signal source for applying signals to be averaged to said second input means.
References Cited (Backward Citations)
US3214706A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |