US3729655A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective circuit arrangement for a switching transistor in an inductive load circuit
Assignee: Siemens AG
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Filing: 1972-08-10
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Granted: 1973-04-24
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Expires: 1992-08-10
Abstract
Abstract A protective circuit arrangement for a switching transistor in an inductive load circuit has a series circuit consisting of a resistor and a controlled auxiliary valve shunted across the collector-emitter path of the switching transistor to take over the load current of the switching transistor when it is switched off. The control electrode of the auxiliary valve is controlled by a control device which consists of a capacitor and a charging resistor in series. A Zener diode may be shunted across the control device. The protective circuit arrangement may be used particularly in an inverter which has a plurality of switching transistors.
Inventors
- 👤 W Gratzke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:40
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/32; H02H; H02H9/00; H02H9/005; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5387; H02M7/53871; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/60; H03K17/64
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
81 words
A protective circuit arrangement for a switching transistor, said switching transistor being arranged in an inductive load circuit for switching the load current on and off, said protective circuit arrangement comprising: a. a series circuit comprising a resistor and a controlled auxiliary valve, said series circuit being shunted across the collector-emitter path of said switching transistor; and b. a control device for controlling the control electrode of said auxiliary valve as a function of the voltage rise at said switching transistor.
Claim 2
Dependent Claim
81 words
A protective circuit arrangement for a switching transistor, said switching transistor being arranged in an inductive load circuit for switching the load current on and off, said protective circuit arrangement comprising: a. a series circuit comprising a resistor and a controlled auxiliary valve, said series circuit being shunted across the collector-emitter path of said switching transistor; and b. a control device for controlling the control electrode of said auxiliary valve as a function of the voltage rise at said switching transistor.
Claim 3
Dependent Claim
16 words
The protective circuit arrangement according to claim 1 wherein said controlled auxiliary valve is a transistor.
Claim 4
Dependent Claim
43 words
The protective circuit arrangement according to claim 2 wherein said control device comprises a series circuit of a capacitor and a charging resistor, said control device being connected between the control electrode of said auxiliary valve and the collector of said switching transistor.
Claim 5
Dependent Claim
63 words
The protective circuit arrangement according to claim 3 and further comprising a Zener diode, said Zener diode being shunted across said series circuit comprising said capacitor and said charging resistor, the Zener voltage of said Zener diode being chosen so that said auxiliary transistor is fully turned on when the Zener voltage value is applied to the control electrode of said auxiliary transistor.
Claim 6
Dependent Claim
17 words
The protective circuit arrangement according to claim 1 wherein said controlled auxiliary valve is an NPN transistor.
Claim 7
Dependent Claim
65 words
The protective circuit arrangement according to claim 5 wherein said resistor of said series circuit being shunted across the collector-emitter path of said switching transistor is connected to the collector of said switching transistor; and the emitter of said npn auxiliary transistor of said series circuit being shunted across the collector-emitter path of the switching transistor is connected to the emitter of the switching transistor.
Claim 8
Dependent Claim
16 words
The protective circuit arrangement according to claim 1 wherein said auxiliary valve is a PNP transistor.
Claim 9
Dependent Claim
51 words
The protective circuit arrangement according to claim 7 wherein said resistor of said series circuit being shunted across the collector-emitter path of said switching transistor is connected to the emitter of said switching transistor; and the emitter of said PNP auxiliary transistor is connected to the collector of said switching transistor.
Claim 10
Dependent Claim
111 words
A protective circuit arrangement adapted for use with an inverter having a plurality of switching transistors, said inverter being connected on the output side to an inductive load and on the input side to a positive input terminal and to a negative input terminal, said protective circuit arrangement comprising: a. a plurality of series circuits each comprising a resistor and a controlled auxiliary valve, each said series circuit being shunted across the collector-Emitter path of one or more of said switching transistors; and b. a plurality of control devices for controlling the control electrode of each said auxiliary valve as a function of the voltage rise at the respective switching transistor.
Claim 11
Dependent Claim
111 words
A protective circuit arrangement adapted for use with an inverter having a plurality of switching transistors, said inverter being connected on the output side to an inductive load and on the input side to a positive input terminal and to a negative input terminal, said protective circuit arrangement comprising: a. a plurality of series circuits each comprising a resistor and a controlled auxiliary valve, each said series circuit being shunted across the collector-Emitter path of one or more of said switching transistors; and b. a plurality of control devices for controlling the control electrode of each said auxiliary valve as a function of the voltage rise at the respective switching transistor.
Claim 12
Dependent Claim
79 words
The protective circuit arrangement according to claim 9 wherein said plurality of switching transistors comprises six switching transistors arranged in two groups, each group comprising three switching transistors, and said protective circuit arrangement comprises: a. two said series circuits, each circuit comprising a resistor and a controlled auxiliary valve, one said series circuit being associated with each said group of three switching transistors; and b. two said control devices, one said control device for each of said series circuits.
Claim 13
Dependent Claim
15 words
The protective circuit arrangement according to claim 10 wherein said controlled auxiliary valves are transistors.
Claim 14
Dependent Claim
55 words
The protective circuit arrangement according to claim 10 wherein said control devices each comprise a series circuit of a capacitor and a charging resistor, each said control device being connected between the control electrode of said auxiliary valve of one of said series circuits and the collectors of one group of said three switching transistors.
Claim 15
Dependent Claim
58 words
The protective circuit arrangement according to claim 10 and further comprising six diodes, one diode for each of the six switching transistors, each diode being connected between its respective switching transistor and the associated series circuit of said protective circuit arrangement, and each diode being poled in the direction of said auxiliary valve of said associated series circuit.
Claim 16
Dependent Claim
44 words
The protective circuit according to claim 10 wherein one said group of three switching transistors is connected to the positive input terminal of said inverter and the other said group of three switching transistors is connected to the negative input terminal of said inverter.
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) | 1976-04-23 | 1976-10-23 | 1977-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-23 | 1980-10-23 | 1981-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-23 | 1984-10-23 | 1985-04-24 | $7700.00 | Window Closed / Lapsed |