US3604949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Monitoring circuits for direct current circuits
Assignee: Robert Bosch GmbH
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Filing: 1970-06-18
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Granted: 1971-09-14
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Expires: 1990-06-18
Abstract
Abstract The voltage drop across a control resistor in the monitored direct current circuit, which drop varies in accordance with the condition of the direct current load, affects the amount of current through a differential amplifier and causes operation of a transistor switch in one of the two collector circuits of the amplifier whenever the load current changes sufficiently. The switch controls an indicating device.
Inventors
- 👤 Gerhard Conzelmann
- 👤 Adolf Kugelmann
- 👤 Heinz Moller
- 👤 Heinz Kammerer
- 👤 Karl-Ernst Boeters
- 👤 Hans-Joachim Fleischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:32
CPC Classifications
B; B60; B60Q; B60Q11/00; B60Q11/005; B60Q11/007
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
268 words
In a circuit of the kind described, a monitored circuit having load means that draws current in dependence on its condition, and two voltage points between which there exists a potential drop that varies in dependence on the current drawn by said load means; and a monitoring circuit for producing a signal whenever the load current indicates a predetermined condition of said load, said monitoring circuit including a reference potential; a differential amplifier having a plurality of transistors, including first and second transistors, common resistance means for the emitters of said first and second transistors, and biasing means for biasing each base of said first and second transistors so that the latter conduct; at least one each of first and second diodes connected with regard to polarities during operation so as to conduct current between the base of a respective one of said first and second transistors and a respective one of said two voltage points, whereby a change in voltage at one of said voltage points affects the collector current in both of said first and second transistors; means connecting the collector of one of said first and second transistors to that one of said two voltage points which is at the greater potential difference with respect to said reference potential; and signal generating means including control switch means, said control switch means being connected between the collector of the other of said first and second transistors and said one voltage point for operation whenever the collector current of said other transistor changes sufficiently in response to a sufficient change in the current through said load means.
Claim 2
Dependent Claim
268 words
In a circuit of the kind described, a monitored circuit having load means that draws current in dependence on its condition, and two voltage points between which there exists a potential drop that varies in dependence on the current drawn by said load means; and a monitoring circuit for producing a signal whenever the load current indicates a predetermined condition of said load, said monitoring circuit including a reference potential; a differential amplifier having a plurality of transistors, including first and second transistors, common resistance means for the emitters of said first and second transistors, and biasing means for biasing each base of said first and second transistors so that the latter conduct; at least one each of first and second diodes connected with regard to polarities during operation so as to conduct current between the base of a respective one of said first and second transistors and a respective one of said two voltage points, whereby a change in voltage at one of said voltage points affects the collector current in both of said first and second transistors; means connecting the collector of one of said first and second transistors to that one of said two voltage points which is at the greater potential difference with respect to said reference potential; and signal generating means including control switch means, said control switch means being connected between the collector of the other of said first and second transistors and said one voltage point for operation whenever the collector current of said other transistor changes sufficiently in response to a sufficient change in the current through said load means.
Claim 3
Dependent Claim
36 words
A monitoring circuit as defined in claim 1, wherein said biasing means are first resistance means connected in the base of said one transistor and second resistance means connected in the base of said other transistor.
Claim 4
Dependent Claim
75 words
A monitoring circuit as defined in claim 2, wherein said switch means comprise a transistor and third resistance means for biasing and connected between the base and the emitter of the transistor of said switch means, the latter transistor being complementary to said other transistor and connected between the collector of the latter and said one voltage point so that its conductive state depends on the amount of the collector current of said other transistor.
Claim 5
Dependent Claim
58 words
A monitoring circuit as defined in claim 3, including a further transistor of which the base is connected to the collector of said switch means transistor, and resistance means connected between the emitter and the base of said further transistor, whereby the conductive state of said further transistor depends on the conductive state of said switch means transistor.
Claim 6
Dependent Claim
23 words
A monitoring circuit as defined in claim 2, including a constant current source connected in the emitters of said first and second transistors.
Claim 7
Dependent Claim
82 words
A monitoring circuit as defined in claim 5, wherein said constant current source includes at least one third transistor of which the collector is connected to the emitters of said fIrst and second transistors; at least one diode conductively connecting the base of said third transistor to a voltage of correct polarity so that said third transistor is biased to conduct; and wherein said common resistance means are connected between said voltage of correct polarity and the emitter of said third transistor.
Claim 8
Dependent Claim
24 words
A monitoring circuit as defined in claim 2, including control resistance means connected in said monitored circuit and across which said potential drop occurs.
Claim 9
Dependent Claim
36 words
A monitoring circuit as defined in claim 2, wherein third resistance means are connected in series with that one of said first and second diodes connected to said one voltage point at the greater potential difference.
Claim 10
Dependent Claim
66 words
A monitoring circuit as defined in claim 8, including a control resistance means connected in said monitored circuit and across which said potential drop occurs, and wherein the desired switching range of said switch means occurs where the resistance ratio of said third resistance means to said first resistance means is approximately equal to that of said control resistance means to said load means under current.
Claim 11
Dependent Claim
139 words
A monitoring circuit as defined in claim 9, wherein said switch means comprise a transistor and third resistance means for biasing and connected between the base and the emitter of the transistor of said switch means, the latter transistor being complementary to said other transistor and connected between the collector of the latter and said one voltage point so that is conductive state depends on the amount of the collector current of said other transistor and so that its direct current input resistance occurs between its base and emitter; and wherein in the emitter of said other transistor of said first and second transistors the resistance resulting from the parallel connection between said third resistance means and the direct current input resistance of the transistor of said switch means has approximately twice the value of said common resistance means.
Claim 12
Dependent Claim
163 words
A monitoring circuit as defined in claim 10, including a constant current source connected in the emitter of said first and second transistors, said constant current source comprising at least one third transistor of which the collector is connected to the emitter of said first and second transistors; and third and fourth diodes in series conductively connecting the base of said third transistor to a voltage of correct polarity so that said third transistor is biased to conduct; and wherein one of said third and fourth diodes consists of the emitter diode of a transistor of the same type as the transistor of said switch means and the other of said third and fourth diodes consists of the emitter diode of a transistor of the same type as said third transistor so as to ensure that the current flowing through said third and fourth diodes is approximately equal to the current flowing through the transistor of said switch means and said third transistor.
Claim 13
Dependent Claim
45 words
A monitoring circuit as defined in claim 11, wherein said load means exhibits a voltage-dependent resistance, and including means for shifting the switching range in dependence on said voltage-dependent resistance, said means including voltage stabilization means for stabilizing the operating voltage for said monitor circuit.
Claim 14
Dependent Claim
33 words
A monitoring circuit as defined in claim 12, wherein said voltage stabilization means include a series connected zener diode and fourth resistance means connected between said reference potential and said one voltage point.
Claim 15
Dependent Claim
68 words
A monitoring circuit as defined in claim 13, including means for adjusting the degree to which the switching range is shifted, said means including a voltage intermediate said reference potential and said one voltage point, and wherein one of said first and second resistance means is connected to said intermediate voltage and has a variable tap, and further resistance means connected between said tap and said reference potential.
Claim 16
Dependent Claim
34 words
A monitoring circuit as defineD in claim 13, including means for adjusting the degree to which the switching range is shifted, said means comprising fifth resistance means connected in series with said zener diode.
Claim 17
Dependent Claim
59 words
A monitoring circuit as defined in claim 15, wherein the series connection of said zener diode and said fourth and fifth resistance means comprises a voltage intermediate said reference potential and said one voltage point, and wherein that one of said first and second resistance means in the base of said one transistor is connected to said intermediate voltage.
Claim 18
Dependent Claim
18 words
A monitoring circuit as defined in claim 16, including a current amplifier connected to furnish said intermediate voltage.
Claim 19
Dependent Claim
18 words
A monitoring circuit as defined in claim 17, wherein said current amplifier comprises a pair of complementary transistors.
Claim 20
Dependent Claim
44 words
A monitoring circuit as defined in claim 1, wherein said monitoring circuit is a monolithic integrated circuit and mutually affecting temperature sensitive components thereof are placed along at least approximate isotherms of the semiconductor crystal so as to reduce temperature differences between these components.
Claim 21
Dependent Claim
39 words
A monitoring circuit as defined in claim 1, wherein all components of said monitored circuit and said monitoring circuit that can be made part of an integrated circuit are combined in a monolithic circuit on a common semiconductor crystal.
References Cited (Backward Citations)
US3103617A
Cited
US3428943A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-13 | 1975-03-15 | 1975-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-13 | 1979-03-15 | 1979-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-13 | 1983-03-15 | 1983-09-14 | $7700.00 | Window Closed / Lapsed |