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Patent US4485311A successfully refreshed from Google Patents.
US4485311A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drive circuit for at least one light-emitting diode
Assignee: Siemens AG
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Filing: 1982-06-04
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Granted: 1984-11-27
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Expires: 2002-06-04
Abstract
Abstract A series connection consisting of a diode and one of two transistors of a transistor push-pull circuit is connected in parallel to the feed current path for a light-emitting diode and a capacitor is interconnected between the junction of the push-pull transistors and the junction between the light-emitting diode and an additional diode which is present in the feed current path. When the transistor in the series connection is in a blocking state, the light-emitting diode receives feed current and is thus switched to a light-emitting state. The capacitor causes a current pulse to be superimposed on the feed current during switchover for rapidly driving the light-emitting diode by decreasing the time span required by the light-emitting diode to reach a condition of maximum light emission.
Inventors
- 👤 Jan Goerne
- 👤 Wilfried Traulsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:01
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/04; H03K17/041; H03K17/0416; H03K17/04166; H03K17/51; H03K17/56; H03K17/60; H03K17/78; H04; H04B; H04B10/00; H04B10/50; H04B10/501; H04B10/502
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
136 words
In a drive circuit for driving at least one light-emitting diode, said light-emitting diode being connected in series with an additional diode which is connected to a source of operating potential through a resistor, said light-emitting diode also connected to a transistor push-pull circuit containing two transistors connected at a junction, the improvement comprising: a connecting diode interconnected between the junction of said resistor and said additional diode and the junction of said two transistors in said transistor push-pull circuit for forming a path to ground with one of said transistors in said push-pull circuit in parallel with said light-emitting diode and said additional diode such that no current is supplied to said light-emitting diode; said additional diode supplying current to said light-emitting diode when said one of said transistors in said push-pull circuit is non-conducting.
Claim 2
Dependent Claim
136 words
In a drive circuit for driving at least one light-emitting diode, said light-emitting diode being connected in series with an additional diode which is connected to a source of operating potential through a resistor, said light-emitting diode also connected to a transistor push-pull circuit containing two transistors connected at a junction, the improvement comprising: a connecting diode interconnected between the junction of said resistor and said additional diode and the junction of said two transistors in said transistor push-pull circuit for forming a path to ground with one of said transistors in said push-pull circuit in parallel with said light-emitting diode and said additional diode such that no current is supplied to said light-emitting diode; said additional diode supplying current to said light-emitting diode when said one of said transistors in said push-pull circuit is non-conducting.
Claim 3
Dependent Claim
47 words
The improvement of claim 1 further comprising: a capacitor interconnected between the junction of said additional diode and said light-emitting diode and the junction of said two transistors in said push-pull circuit for generating a current pulse upon switchover of said light-emitting diode to a conducting state.
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) | 1987-11-27 | 1988-05-28 | 1988-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-27 | 1992-05-28 | 1992-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-27 | 1996-05-28 | 1996-11-27 | $7700.00 | Window Closed / Lapsed |