US3839648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Programmable function generation
Assignee: Tektronix Inc
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Filing: 1973-03-14
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Granted: 1974-10-01
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Expires: 1993-03-14
Abstract
Abstract A programmable function generator, which is suitable for construction in integrated circuit form, includes a current ladder which produces an output voltage or current which is a programmable function of an input voltage or current at n evenly spaced values of the input voltage or current corresponding to n spaced output points along the current ladder. Accurately controlled current sources or current drivers control the flow of currents to each of the n points and the flow of current from terminals of said current ladder including compensated current drivers, one of which differentially controls current flow from end terminals of the current ladder in response to a variable input control voltage or current which, for example, may be a linear ramp of voltage or current.
Inventors
- 👤 J Pace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:03
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/26; G06G7/28; G06G7/30; H; H03; H03G; H03G1/00; H03G1/0005
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
171 words
Differential current driver means for causing linearly varying complementary current flow from a pair of terminals external thereto in response to an externally applied varying signal comprising: means for converting said externally applied varying signal to a varying control current; a pair of current conducting means comprising emitter-couPled transistor means for receiving said complementary current flow from said pair of terminals and for transferring said complementary current flow therebetween in response to said control current, the base current of one of said transistor means being controlled by said control current; current compensating means for receiving said current flow from said current conducting means to stabilize said current flow against change due to temperature variation of said current conducting means, wherein said current compensating means establishes the current therethrough at a standard value plus substantially the value of base current for said conducting means according to the value of beta for the transistor means; and circuit means to linearize the transfer of said current flow between said pair of current conducting means.
Claim 2
Dependent Claim
171 words
Differential current driver means for causing linearly varying complementary current flow from a pair of terminals external thereto in response to an externally applied varying signal comprising: means for converting said externally applied varying signal to a varying control current; a pair of current conducting means comprising emitter-couPled transistor means for receiving said complementary current flow from said pair of terminals and for transferring said complementary current flow therebetween in response to said control current, the base current of one of said transistor means being controlled by said control current; current compensating means for receiving said current flow from said current conducting means to stabilize said current flow against change due to temperature variation of said current conducting means, wherein said current compensating means establishes the current therethrough at a standard value plus substantially the value of base current for said conducting means according to the value of beta for the transistor means; and circuit means to linearize the transfer of said current flow between said pair of current conducting means.
Claim 3
Dependent Claim
18 words
The circuit of claim 1 wherein said means for converting said externally applied signal comprises operational amplifier means.
Claim 4
Dependent Claim
94 words
The circuit of claim 1 wherein said compensating means includes a first transistor having a predetermined current flow therethrough; and wherein said circuit means comprises diode means for connecting the major portion of said control current to said first transistor and for producing a voltage drop in response to said control current to control said current conducting means to thereby linearize the transfer of current between said current conducting means; the predetermined current of said first transistor being established at a standard value less substantially the value of base current of said conducting means.
Claim 5
Dependent Claim
130 words
The circuit of claim 3 wherein said compensating means further includes: a current source for providing a current at said standard value; second, third and fourth transistors; the said first, second and third transistors having their bases coupled in common and having their emitters coupled in common to a voltage source, the collector of the third transistor being coupled to said current source; and means for coupling the base of the fourth transistor to the collector of the third transistor, and for coupling the emitter of the fourth transistor to the collector of the second transistor as well as to the common base coupling of the first, second and third transistors; wherein the collector of the fourth transistor is coupled to receive said current flow from said current conducting means.
Claim 6
Dependent Claim
158 words
A current compensating circuit comprising: a current source for providing a current at a standard value; first, second, third and fourth transistors wherein the first, second and third transistors have their bases coupled in common and have their emitters coupled in common to a voltage source, the collector of the third transistor being coupled to said current source; and means for coupling the base of the fourth transistor to the collector of the third transistor, and for coupling the emitter of the fourth transistor to the collector of the second transistor as well as to the common base coupling of the first, second and third transistors; wherein the collector of the fourth transistor provides a current at said standard value plus substantially the value of transistor base current as governed by the value of beta of said transistors, and wherein the first transistor provides a current at the standard value minus substantially the value of said base current.
Claim 7
Dependent Claim
158 words
A current compensating circuit comprising: a current source for providing a current at a standard value; first, second, third and fourth transistors wherein the first, second and third transistors have their bases coupled in common and have their emitters coupled in common to a voltage source, the collector of the third transistor being coupled to said current source; and means for coupling the base of the fourth transistor to the collector of the third transistor, and for coupling the emitter of the fourth transistor to the collector of the second transistor as well as to the common base coupling of the first, second and third transistors; wherein the collector of the fourth transistor provides a current at said standard value plus substantially the value of transistor base current as governed by the value of beta of said transistors, and wherein the first transistor provides a current at the standard value minus substantially the value of said base current.
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) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |