US3568043A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diode constant voltage source limits current through a series transistor circuit
Assignee: Robert Bosch GmbH
•
Filing: 1969-04-10
•
Granted: 1971-03-02
•
Expires: 1989-04-10
Abstract
Abstract To provide a self-protecting feature in case of malconnection or malfunction of the load, a transistor controlling an electromagnetic operating circuit has connected a sensing resistance in series with its emitter-collector path, a constant voltage source formed of diodes from the current source (battery) to the emitter, and a comparison resistance connected across the emitter-base terminals of the transistor, the relative values of the sensing resistance, the comparison resistance and the voltage of the constant voltage source being so selected relative to each other that under ordinary operating conditions the emitter-base potential is sufficient to provide full conduction of the transistor, whereas, upon decrease of total resistance of the emitter-collector circuit, the transistor is controlled to assume a high resistance value and limit the flow of current therethrough to a safe value.
Inventors
- 👤 Friedrich Rabus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:57
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/08; H03K17/082; H03K17/0826
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
300 words
A self- protecting automotive transistorized electromagnetic operating circuit controlled by a power transistor (5) and adapted for connection to a vehicle battery (3), said electromagnetic operating circuit including an electromagnetic operating device (4, 14) of predetermined resistance and the emitter-collector path of the power transistor (5) connected in series with said electromagnetic operating device, said series connected circuit being connected across the vehicle battery (3) comprising: a sensing resistance (6) connected between the emitter of said power transistor (5) and one pole (2) of the vehicle battery (3); a diode means (9, 10) having one terminal connected in forwardly conductive direction to said one pole (2) of the battery (3); a resistance means (8, 19) connected at one end to the other pole of the battery (3) and at the other end to the emitter of said power transistor and to the other terminal of said diode means (9, 10) to supply current through said diode means whereby said diode means will function as a constant voltage source; and a comparison resistance (11) connected across the emitter-base terminals of the power transistor (5), and to the other terminal of said diode, the voltage values sensed by said sensing resistance (6) and said resistance (11), and the value of the constant voltage arising across said diode (9,10) being selected relative to each other to provide an emitter-base potential across said power transistor (5) sufficient for full conduction of said transistor upon normal current flow through its emitter-collector path and through the sensing resistance (6) and, upon decrease of the total resistance of said electromagnetic operating circuit from said predetermined value, causing normal current flow by providing an emitter-base potential of sufficient value to control the transistor to assume a higher resistance and permit flow of current of a safe level only.
Claim 2
Dependent Claim
300 words
A self- protecting automotive transistorized electromagnetic operating circuit controlled by a power transistor (5) and adapted for connection to a vehicle battery (3), said electromagnetic operating circuit including an electromagnetic operating device (4, 14) of predetermined resistance and the emitter-collector path of the power transistor (5) connected in series with said electromagnetic operating device, said series connected circuit being connected across the vehicle battery (3) comprising: a sensing resistance (6) connected between the emitter of said power transistor (5) and one pole (2) of the vehicle battery (3); a diode means (9, 10) having one terminal connected in forwardly conductive direction to said one pole (2) of the battery (3); a resistance means (8, 19) connected at one end to the other pole of the battery (3) and at the other end to the emitter of said power transistor and to the other terminal of said diode means (9, 10) to supply current through said diode means whereby said diode means will function as a constant voltage source; and a comparison resistance (11) connected across the emitter-base terminals of the power transistor (5), and to the other terminal of said diode, the voltage values sensed by said sensing resistance (6) and said resistance (11), and the value of the constant voltage arising across said diode (9,10) being selected relative to each other to provide an emitter-base potential across said power transistor (5) sufficient for full conduction of said transistor upon normal current flow through its emitter-collector path and through the sensing resistance (6) and, upon decrease of the total resistance of said electromagnetic operating circuit from said predetermined value, causing normal current flow by providing an emitter-base potential of sufficient value to control the transistor to assume a higher resistance and permit flow of current of a safe level only.
Claim 3
Dependent Claim
31 words
Self-protecting, automotive circuit according to claim 1 wherein the electromagnetic operating device is a relay (14) having its coil connected in series with the emitter-collector path of the power transistor (5).
Claim 4
Dependent Claim
79 words
Self-protecting automotive circuit according to claim 1 wherein a plurality of diodes (9, 10) are provided, connected in series, the number of diodes and the value of said resistance means (8. 19) being selected to provide a constant voltage (U2) across said diodes which is equal to the voltage drop (U1) across the diode path formed by the base-emitter half of the power transistor (5) and the voltage drop (U3) across the sensing resistaNce (6) under normal current flow.
Claim 5
Dependent Claim
155 words
Self-protecting overcurrent circuit for power transistors in which the emitter-collector circuit of the power transistor (5) is adapted for connection, in series, with an electric source (3) and a load, (4, 14) comprising: a measuring resistance (6) connected in series with the emitter-collector circuit of the power transistor (5) and developing a sensing voltage (U3) thereacross; diode means (9, 10) connected in forward conductive direction across said source and deriving a fixed voltage (U2); and means connecting said diode means to the base of said power transistor (5) to provide a pair of parallel paths having said fixed voltage (U2) across the diode path and the sum of said sensing voltage U3) and the emitter-base voltage (U1) of said power transistor (5) across the other path said emitter-base voltage (O1) decreasing with increasing sensing voltage (U3) to control the transistor in a direction of decreasing conduction upon increase of current through said measuring resistance (6).
Claim 6
Dependent Claim
155 words
Self-protecting overcurrent circuit for power transistors in which the emitter-collector circuit of the power transistor (5) is adapted for connection, in series, with an electric source (3) and a load, (4, 14) comprising: a measuring resistance (6) connected in series with the emitter-collector circuit of the power transistor (5) and developing a sensing voltage (U3) thereacross; diode means (9, 10) connected in forward conductive direction across said source and deriving a fixed voltage (U2); and means connecting said diode means to the base of said power transistor (5) to provide a pair of parallel paths having said fixed voltage (U2) across the diode path and the sum of said sensing voltage U3) and the emitter-base voltage (U1) of said power transistor (5) across the other path said emitter-base voltage (O1) decreasing with increasing sensing voltage (U3) to control the transistor in a direction of decreasing conduction upon increase of current through said measuring resistance (6).
Claim 7
Dependent Claim
70 words
Circuit according to claim 4 wherein said means deriving a fixed voltage comprises a plurality of diodes (9, 10) connected in series, and said series connected diodes being connected across said measuring resistance (6) and the emitter-base circuit of said transistor (5), whereby, upon increasing current through the measuring resistance, the voltage across said emitter-base path of transistor (5) will drop to increase the resistance of the power transistor (5).
Claim 8
Dependent Claim
21 words
Circuit according to claim 4, including a comparative resistance (11) connected directly across the emitter-base terminals of the power transistor (5).
Claim 9
Dependent Claim
26 words
Circuit according to claim 4 wherein said load comprises a relay (14) having its coil connected in series with the emitter-collector path of the transistor (5).
Claim 10
Dependent Claim
68 words
Circuit according to claim 4 including a resistance means (8, 19) connected at one end of a pole (1) of the source (3) and at the other end to the base of said power transistor and thus forming said connecting means to said diode means to supply current through said diode means, whereby said diode means will function as a fixed voltage source supplying said fixed voltage (U2).
Claim 11
Dependent Claim
21 words
Circuit according to claim 8 wherein said diode means comprises a plurality of series connected diodes, all connected in forward-conductive direction.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |