US5451845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for protecting a ballast circuit from excess voltage
Assignee: Knobel AG Lichttechnische Komponenten
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Filing: 1994-07-26
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Granted: 1995-09-19
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Expires: 2014-07-26
Abstract
Abstract A device for protecting a ballast circuit from excess voltage and excess current includes a switch for disconnecting the ballast circuit from the power source and a control circuit for operating this switch; the control circuit monitoring a control point, from which control point a first resistor connects to a first terminal of the power source, a second resistor connects to a second terminal of the power source, and a third resistor connects to a point between the switch and the ballast, the switch being brought into off-state when the voltage between the control point and the first terminal of the power source exceeds a given value, thus leading to a hysteresis between an input voltage for switching the device off and an input voltage for switching the device back on again, with positive feedback being provided by the third resistor for decreasing the switch-off time and the corresponding switching losses.
Inventors
- 👤 Thomas Ribarich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:59
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/001; H02H3/00; H02H3/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
113 words
A device for protecting a ballast circuit from excess voltages in a power source, the device comprising: an electronic switch substantially arranged in series with the ballast between a first power terminal of the power source and a first input terminal of the ballast circuit; a driving circuit for driving the electronic switch, the driving circuit comprising a threshold voltage monitor for monitoring a control voltage between a control point and the first power terminal; wherein the control point is connected to the first power terminal, through a first resistor, to a second power terminal of the power source, through a second resistor, and to the first input terminal through a third resistor.
Claim 2
Independent Claim
113 words
A device for protecting a ballast circuit from excess voltages in a power source, the device comprising: an electronic switch substantially arranged in series with the ballast between a first power terminal of the power source and a first input terminal of the ballast circuit; a driving circuit for driving the electronic switch, the driving circuit comprising a threshold voltage monitor for monitoring a control voltage between a control point and the first power terminal; wherein the control point is connected to the first power terminal, through a first resistor, to a second power terminal of the power source, through a second resistor, and to the first input terminal through a third resistor.
Claim 3
Dependent Claim
25 words
The device of claim 1 wherein the threshold voltage monitor opens the switch for disconnecting the ballast when the control voltage exceeds a threshold voltage.
Claim 4
Dependent Claim
35 words
The device of claim 2, wherein the threshold voltage monitor comprises at least one Zener diode for determining the threshold voltage and wherein a current in the Zener diode causes the switch to be opened.
Claim 5
Dependent Claim
34 words
The device of claim 3 wherein the Zener diode is connected to a base of a transistor and wherein a closing of the transistor causes a control voltage of the switch to be decreased.
Claim 6
Independent Claim
28 words
The device of claim i further comprising a thyristor circuit and means for triggering the thyristor circuit when a current in the switch exceeds a maximum current value.
Claim 7
Dependent Claim
38 words
The device of claim 4 further comprising a thyristor circuit and means for triggering the thyristor circuit when a current in the switch exceeds a maximum current value, wherein the thyristor circuit is arranged parallel with the transistor.
Claim 8
Dependent Claim
14 words
The device of claim 1 wherein the switch is an N-channel field effect transistor.
Claim 9
Dependent Claim
14 words
The device of claim 1 wherein the switch is an insulated gate bipolar transistor.
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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) | 1998-09-18 | 1999-03-20 | 1999-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-18 | 2003-03-20 | 2003-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-18 | 2007-03-20 | 2007-09-19 | $7700.00 | Window Closed / Lapsed |