US4564769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Saturation control of a switching transistor
Assignee: Danfoss AS
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Filing: 1983-09-12
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Granted: 1986-01-14
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Expires: 2003-09-12
Abstract
Abstract The invention relates to a base control circuit for a switching transistor in which diodes are utilized to maintain the base-emitter voltage at a higher level than the collector-emitter voltage, upon the turn-on voltage being applied, to minimize switching-on losses while operating to avoid saturation.
Inventors
- 👤 Anna Melamed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:22
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/04; H03K17/042; H03K17/0422; H03K17/06; H03K17/51; H03K17/56; H03K17/60; H03K17/601
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
143 words
A transistor circuit comprising a switching transistor having a base, collector and emitter, a load and a DC power supply in series with the collector-emitter path of said transistor, a control input terminal, a base circuit diode connected between said input and said base poled to conduct current in the same direction as the base-emitter junction of said transistor, a current amplifier connected between said base circuit diode and said base, a saturation control circuit connected between said input and said collector including first and second diodes in series poled to conduct current towards said collector, said diodes interacting so that upon a switch-on voltage being applied to said input the base-emitter voltage is higher than the collector-emitter voltage an amount approximating the difference between the voltage drop across said first and second diodes and the voltage drop across said base circuit diode.
Claim 2
Dependent Claim
143 words
A transistor circuit comprising a switching transistor having a base, collector and emitter, a load and a DC power supply in series with the collector-emitter path of said transistor, a control input terminal, a base circuit diode connected between said input and said base poled to conduct current in the same direction as the base-emitter junction of said transistor, a current amplifier connected between said base circuit diode and said base, a saturation control circuit connected between said input and said collector including first and second diodes in series poled to conduct current towards said collector, said diodes interacting so that upon a switch-on voltage being applied to said input the base-emitter voltage is higher than the collector-emitter voltage an amount approximating the difference between the voltage drop across said first and second diodes and the voltage drop across said base circuit diode.
Claim 3
Dependent Claim
171 words
A transistor circuit comprising a switching transistor having a base, collector and emitter, a load and a DC power supply in series with the collector-emitter path of said transistor, a control input terminal, a base circuit diode connected between said input and said base poled to conduct current in the same direction as the base-emitter junction of said transistor, a saturation control circuit connected between said input and said collector including first and second diodes in series poled towards said collector, an over-voltage diode connected between the junction of said first and second diodes and ground and being poled to conduct current towards ground, and a low voltage source connected between said over-voltage diode and ground poled to conduct current towards said over-voltage diode, said diodes interacting so that upon a switch-on voltage being applied to said input the base-emitter voltage is higher than the collector-emitter voltage an amount approximating the difference between the voltage drop across said first and second diodes and the voltage drop across said base circuit diode.
Claim 4
Dependent Claim
171 words
A transistor circuit comprising a switching transistor having a base, collector and emitter, a load and a DC power supply in series with the collector-emitter path of said transistor, a control input terminal, a base circuit diode connected between said input and said base poled to conduct current in the same direction as the base-emitter junction of said transistor, a saturation control circuit connected between said input and said collector including first and second diodes in series poled towards said collector, an over-voltage diode connected between the junction of said first and second diodes and ground and being poled to conduct current towards ground, and a low voltage source connected between said over-voltage diode and ground poled to conduct current towards said over-voltage diode, said diodes interacting so that upon a switch-on voltage being applied to said input the base-emitter voltage is higher than the collector-emitter voltage an amount approximating the difference between the voltage drop across said first and second diodes and the voltage drop across said base circuit diode.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-13 | 1989-07-15 | 1990-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-13 | 1993-07-15 | 1994-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-13 | 1997-07-15 | 1998-01-14 | $7700.00 | Window Closed / Lapsed |