US5410220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuit for drive circuit of an electronic ballast for a discharge lamp
Assignee: Helvar Oy AB
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Filing: 1993-09-16
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Granted: 1995-04-25
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Expires: 2013-09-16
Abstract
Abstract The invention relates to an electronic ballast for a discharge lamp, comprising a drive circuit supplying high-frequency current to the lamp and including two power switches (V1, V2) and control circuits therefor for controlling the power switches, such that the parallel half-waves of the lamp current pass through a first power switch (V1) and the reverse half-waves through a second power switch. Each power switch (V1; V2) is provided with its own, independently operating control circuit and each control circuit is provided with means (R1, R3, R8, R7) for sensing a current passing through and a voltage prevailing across the appropriate power switch (V1; V2) as well as with means (V3; V4) for controllably bringing the appropriate power switch (V1; V2) to a conducting state as a certain voltage prevails thereacross and to a non-conducting state as soon as a current passing therethrough reaches a certain threshold value (Ik; Ikl).
Inventors
- 👤 Kari von Hertzen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:14
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5383; H02M7/53832; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; H05B41/282; H05B41/2825; H05B41/2828; Y; Y02; Y02B; Y02B20/00; Y10; Y10S; Y10S315/00; Y10S315/05; Y10S315/07
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
132 words
An electronic ballast for a discharge lamp, comprising a drive circuit supplying high-frequency current to the lamp and including two power switches (V1, V2) and control circuits therefor for controlling the power switches, such that the parallel half-waves of the lamp current pass through a first power switch (V1) and the reverse half-waves through a second power switch, characterized in that control circuits (R1, R3, R8, R7, V3/R2, R4, R9, R7, V4) are functionally independent, such that a switch of condition of power switches (V1/V2) is determined on the basis of a current passing through the very power switch (V1/V2) being controlled as well as on the basis of the dimensions of control circuits (R1, R3, R8, R7, V3/R2, R4, R9, R7, V4) and/or on the basis of an external control (Uohj.).
Claim 2
Dependent Claim
132 words
An electronic ballast for a discharge lamp, comprising a drive circuit supplying high-frequency current to the lamp and including two power switches (V1, V2) and control circuits therefor for controlling the power switches, such that the parallel half-waves of the lamp current pass through a first power switch (V1) and the reverse half-waves through a second power switch, characterized in that control circuits (R1, R3, R8, R7, V3/R2, R4, R9, R7, V4) are functionally independent, such that a switch of condition of power switches (V1/V2) is determined on the basis of a current passing through the very power switch (V1/V2) being controlled as well as on the basis of the dimensions of control circuits (R1, R3, R8, R7, V3/R2, R4, R9, R7, V4) and/or on the basis of an external control (Uohj.).
Claim 3
Dependent Claim
49 words
A ballast as set forth in claim 1, characterized in that said control circuits (R1, R3, R8, R7, V3/R2, R4, R9, R7, V4) can be separated from each other, i.e. there is no data transmission link therebetween for determining the switch-on or switch-off instant of power switches (V1, V2).
Claim 4
Dependent Claim
39 words
A ballast as set forth in claim 1, characterized in that said control circuits (R1, R3, R8, R7, V3/R2, R4, R9, R7, V4) are directly, without a high-voltage differential connected to the appropriate power switch supplying the lamp current.
Claim 5
Dependent Claim
49 words
A ballast as set forth in claim 1, characterized in that each control circuit is provided with means (R1/R2) for sensing a current passing through the appropriate power switch (V1/V2) as well as with means (V3/V4) for controlling the appropriate power switch (V1/V2) in accordance with said current measurement.
Claim 6
Dependent Claim
82 words
A ballast as set forth in claim 4, characterized in that each control circuit is provided with means (R1, R3, R8, R7/R2, R4, R9, R7) for sensing a current passing through and a voltage prevailing across the appropriate power switch (V1/V2) as well as with means (V3/V4) for controllably bringing the appropriate power switch (V1/V2) to a conducting state as a certain voltage prevails thereacross and to a non-conducting state as soon as a current passing therethrough reaches a certain value (Ik/Ikl).
Claim 7
Dependent Claim
104 words
A ballast as set forth in claim 5, characterized in that in each control circuit, said control means include a semiconductor switch (V3/V4), connected between a power switch control electrode and a lower potential and having its control electrode connected on the one hand to a first point located between power switch (V1/V2) and a resistance (R1/R2) in series therewith and, on the other hand, to a second point by way of a shunt connection formed by a resistance (R8/R9) and a capacitor (C1/C2), said second point being essentially at the same potential as an anode (D) included in the appropriate power switch (V1/V2).
Claim 8
Dependent Claim
67 words
A ballast as set forth in claim 1, characterized in that between power switches (V1/V2) there is a point (A) and between this point and a lamp (DL) is a current restricting inductance (Le) provided with means (Lt, V9, V10, Uhehk.) for varying the value of inductance (Le), such that the drive circuit Can be operated at a higher frequency during the switch-on period of a lamp.
Claim 9
Dependent Claim
18 words
A ballast as set forth in claim 1, characterized in that said power switches (V1/V2) are MOSFET transistors.
Claim 10
Dependent Claim
38 words
A ballast as set forth in claim 5, characterized in that each control circuit is provided with an input for external control voltage (Uohj), such that said current value (Ik/Ilk) can be varied by varying the control voltage.
Claim 11
Dependent Claim
38 words
A ballast as set forth in claim 6, characterized in that each control circuit is provided with an input for external control voltage (Uohj), such that said current value (Ik/Ilk) can be varied by varying the control voltage.
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) | 1998-04-24 | 1998-10-24 | 1999-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-24 | 2002-10-24 | 2003-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-24 | 2006-10-24 | 2007-04-25 | $7700.00 | Window Closed / Lapsed |