WO2009056431A2 - A ballast circuit - Google Patents

A ballast circuit Download PDF

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Publication number
WO2009056431A2
WO2009056431A2 PCT/EP2008/063565 EP2008063565W WO2009056431A2 WO 2009056431 A2 WO2009056431 A2 WO 2009056431A2 EP 2008063565 W EP2008063565 W EP 2008063565W WO 2009056431 A2 WO2009056431 A2 WO 2009056431A2
Authority
WO
WIPO (PCT)
Prior art keywords
fluorescent lamps
lamps
resonance
ballast
capacitor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2008/063565
Other languages
French (fr)
Other versions
WO2009056431A3 (en
Inventor
Wei Chen
Markus Heckmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osram GmbH
Original Assignee
Osram GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Osram GmbH filed Critical Osram GmbH
Priority to EP08845841A priority Critical patent/EP2206414B1/en
Priority to PL08845841T priority patent/PL2206414T3/en
Priority to AT08845841T priority patent/ATE538625T1/en
Publication of WO2009056431A2 publication Critical patent/WO2009056431A2/en
Publication of WO2009056431A3 publication Critical patent/WO2009056431A3/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters
    • H05B41/295—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps
    • H05B41/298—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2981—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
    • H05B41/2985—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against abnormal lamp operating conditions

Definitions

  • the invention relates to a ballast circuit, specifically a ballast circuit for running multiple fluorescent lamps.
  • ballast topologies with multiple parallel load circuits for running plural fluorescent lamps the element tolerances of the resonance circuit generally cause unbalanced resonance characteristics in the circuit. Also different load situations (e.g. a broken lamp) will cause severe imbalance in the ballast topologies. This results overload conditions, which are critical for conventional halfbridge switches and thus demand for a solution of high rate components.
  • the object of the invention is to provide an arrangement of ballast topologies for running multiple fluorescent lamps, in which no unbalance occurs even one of the fluorescent lamps is broken.
  • sequence start capacitors for multiple lamps operation is well known in the ail. However taking advantage of those sequence start capacitors to solve the unbalance caused by asymmetric LC resonance in
  • the multiple fluorescent lamps are connected in series and divided into groups of every two lamps- comprising: LC resonance circuits for igniting respective groups of the two fluorescent lamps, each of the resonance circuits is formed with a resonance capacitor and a coil and connected between the corresponding group of the lamps and ground; a DC block capacitor for conducting the electric current from the resonance capacitor to ground, wherein the ballast circuit further comprising sequence start capacitors (C3, C4) that are connected through the filaments between both LC resonance circuits when there are two fluorescent lamps, or connected from each LC resonance circuit to the connection point of the other group of lamps when there are more than two fluorescent lamps, for limiting the electric voltage generated on the respective resonance capacitor when one of the lamps is broken in a corresponding group of
  • the sequence start capacitors in parallel between LC resonance circuits are connected to other LC resonance circuit in a multiple lamp operation.
  • the problem of asymmetric LC resonance in parallel circuit is solved and the multiple lamp operation is implemented.
  • FIG. 1 shows an embodiment of the invention, in which a ballast circuit runs two lamps;
  • Fig. 2 shows another embodiment of the invention, in which a ballast circuit runs four lamps.
  • Fig. 1 shows an embodiment of the invention, in which a ballast circuit runs two lamps.
  • the ballast circuit is labeled by 2*L3 ⁇ W circuit.
  • Lamp 1 and Lamp 2 indicate two lamps connected in series.
  • Capacitors Cl and C2 arc ignition capacitors.
  • C4 are sequence start capacitors, and a capacitor CS is a DC block capacitor.
  • Coils L 1 and L2 have a function as a lamp choke respectively.
  • the capacitors C3 and C4 are connected through the filaments between both LC resonance circuits. When a lamp Lamp 1, is broken, the coil Ll and capacitor Cl will generate a very high ignition voltage due to an asymmetric circuit load.
  • the sequence start capacitors C3 and C4 some of the current from the capacitor Cl is bypassed to the capacitor C5, the voltage of the capacitor Cl thus is decreased and limited, and the asymmetric resonance in the circuit is eliminated
  • FIg. 2 shows another embodiment of the invention, in which the ballast circuit runs four lamps.
  • the ballast circuit is labeled by 4*L18W circuit.
  • Lamp 1, Lamp 2, Lamp 3 and Lamp 4 indicate four lamps connected in series.
  • Capacitors Cl and C2 in respective LC resonance circuits are ignition capacitors.
  • Capacitors C3 and C4 are
  • a capacitor CS is a DC block capacitor.
  • Colls Ll and L2 in respective LC resonance circuits have a function as a lamp choke respectively.
  • the four lamps are divided into two groups, one group comprises lamps Lamp 1 and Lamp 2, the other comprises lamps Lamp 3 and Lamp 4.
  • the four lamps are connected in series, while the respective LC resonance circuits of each group are connected in parallel.
  • the connection of the capacitors C3 and C4 is in a way extended from that shown in Fig. 1.
  • the capacitors C3 and C4 are connected to every other lamps, i.e. the capacitor C3 is connected across lamps Lamp 2 and
  • Lamp 4 and capacitor C4 is connected across lamps Lamp 1 and Lamp 3.
  • the sequence start capacitors C3 and C4 are connected from each LC resonance circuit to the series connection point of the other group of lamps.
  • the sequence start capacitors C3 and C4 are connected from each LC resonance circuit to the series connection point of the other group of lamps.
  • the ballast topologies further comprise two switches U l and U2 for connecting the resonance circuits to a power supply.
  • the capacitance values range of the sequence start capacitors C3 and C4 is from 14OpF to 4.9nF
  • the capacitance values range of the resonance capacitors C l and C2 in the LC resonance circuits can be selected from 90OpF to 16nF
  • the induction values range of the coils Ll and L2 in the resonance circuits is from 950 ⁇ H to 8.4mH.
  • the intended capacitance values range of the sequence start capacitors C3 and C4 is from 2OpF to 90OpF
  • the intended capacitance values range of the resonance capacitors C l and C2 in the LC resonance circuits can be selected from 20OpF to B. ⁇ nF
  • the intended induction values range of the coils L l and L2 in the resonance circuits is from l 90 ⁇ H to 1.6mH.
  • the number of the lamps in the topologies is not limited to the above-mentioned embodiments.
  • the principle of the invention can be used for any other type of fluorescent lamps and also can be extended to any number of parallel resonance circuits.
  • a person skilled in the art could change or modify the circuit arrangement without exceeding the essence of the invention.
  • the changes and modifications belong to the range of the invention as set forth in claims.

Landscapes

  • Circuit Arrangements For Discharge Lamps (AREA)
  • Discharge Heating (AREA)

Abstract

The invention relates to a ballast circuit for running multiple fluorescent lamps of at least two fluorescent lamps, the multiple fluorescent lamps are connected in series and divided into groups of every two lamps, comprising: LC resonance circuits for igniting respective groups of the two fluorescent lamps, a DC block capacitor for conducting the electric current from the resonance capacitor to ground, wherein the ballast circuit further comprising sequence start capacitors (C3, C4) that are connected through the filaments between both LC resonance circuits when there are two fluorescent lamps, or connected from each LC resonance circuit to the connection point of the other group of lamps when there are more than two fluorescent lamps, for limiting the electric voltage generated on the respective resonance capacitor when one of the lamps is broken in a corresponding group of fluorescent lamps.

Description

DESCRIPTION
A BALLAST CIRCUIT
Technical Field
The invention relates to a ballast circuit, specifically a ballast circuit for running multiple fluorescent lamps.
Bachground Art In ballast topologies with multiple parallel load circuits for running plural fluorescent lamps, the element tolerances of the resonance circuit generally cause unbalanced resonance characteristics in the circuit. Also different load situations (e.g. a broken lamp) will cause severe imbalance in the ballast topologies. This results overload conditions, which are critical for conventional halfbridge switches and thus demand for a solution of high rate components.
Basically in the art there are possibilities known to balance multiple load circuits by arranging a well-defined coupling between the different load circuits. However, such arrangements require more additional capacitors and/or magnetic elements that leads to compelexity in manufacturing process and will cause a cost-effectiveness problem in popular production.
Contents of the Invention The object of the invention is to provide an arrangement of ballast topologies for running multiple fluorescent lamps, in which no unbalance occurs even one of the fluorescent lamps is broken.
Using sequence start capacitors for multiple lamps operation is well known in the ail. However taking advantage of those sequence start capacitors to solve the unbalance caused by asymmetric LC resonance in
.. i parallel circuit is a new idea. Therefore the fundamental idea of the invention is to use the already existing sequence start capacitors to set the required coupling of multiple load circuits. The object is achieved by a following solution. According to a ballast circuit for running multiple Ωuorescent lamps of at least two fluorescent lamps of the invention, the multiple fluorescent lamps are connected in series and divided into groups of every two lamps- comprising: LC resonance circuits for igniting respective groups of the two fluorescent lamps, each of the resonance circuits is formed with a resonance capacitor and a coil and connected between the corresponding group of the lamps and ground; a DC block capacitor for conducting the electric current from the resonance capacitor to ground, wherein the ballast circuit further comprising sequence start capacitors (C3, C4) that are connected through the filaments between both LC resonance circuits when there are two fluorescent lamps, or connected from each LC resonance circuit to the connection point of the other group of lamps when there are more than two fluorescent lamps, for limiting the electric voltage generated on the respective resonance capacitor when one of the lamps is broken in a corresponding group of fluorescent lamps. The invention also covers the embodiments based on the above-mentioned solution,
In the invention, the sequence start capacitors in parallel between LC resonance circuits are connected to other LC resonance circuit in a multiple lamp operation. By the solution of the invention, the problem of asymmetric LC resonance in parallel circuit is solved and the multiple lamp operation is implemented.
Description of Figures
The invention is explained with reference to the figures as below, in which:
_ o _ Fig. 1 shows an embodiment of the invention, in which a ballast circuit runs two lamps;
Fig. 2 shows another embodiment of the invention, in which a ballast circuit runs four lamps.
Mode of Carrying Out the Invention
Fig. 1 shows an embodiment of the invention, in which a ballast circuit runs two lamps. The ballast circuit is labeled by 2*L3όW circuit.
As shown in Fig. 1, Lamp 1 and Lamp 2 indicate two lamps connected in series. Capacitors Cl and C2 arc ignition capacitors. Capacitors C3 and
C4 are sequence start capacitors, and a capacitor CS is a DC block capacitor. Coils L 1 and L2 have a function as a lamp choke respectively. The capacitors C3 and C4 are connected through the filaments between both LC resonance circuits. When a lamp Lamp 1, is broken, the coil Ll and capacitor Cl will generate a very high ignition voltage due to an asymmetric circuit load. By means of the sequence start capacitors C3 and C4, some of the current from the capacitor Cl is bypassed to the capacitor C5, the voltage of the capacitor Cl thus is decreased and limited, and the asymmetric resonance in the circuit is eliminated
The same process is carried out for the lamp Lamp 2. When the lamp Lamp 2 is broken, a very high voltage that will be generated by L2 and C2 is bypassed to the capacitor C5 by means of sequence start capacitors C3 and C4 so that the voltage on the capacitor C2 is limited to keep the balance in resonance in circuit.
FIg. 2 shows another embodiment of the invention, in which the ballast circuit runs four lamps. The ballast circuit is labeled by 4*L18W circuit. As shown in Fig. 2, Lamp 1, Lamp 2, Lamp 3 and Lamp 4 indicate four lamps connected in series. Capacitors Cl and C2 in respective LC resonance circuits are ignition capacitors. Capacitors C3 and C4 are
-> sequence start capacitors, and a capacitor CS is a DC block capacitor.
Colls Ll and L2 in respective LC resonance circuits have a function as a lamp choke respectively.
The four lamps are divided into two groups, one group comprises lamps Lamp 1 and Lamp 2, the other comprises lamps Lamp 3 and Lamp 4. The four lamps are connected in series, while the respective LC resonance circuits of each group are connected in parallel.
The connection of the capacitors C3 and C4 is in a way extended from that shown in Fig. 1. The capacitors C3 and C4 are connected to every other lamps, i.e. the capacitor C3 is connected across lamps Lamp 2 and
Lamp 4, and capacitor C4 is connected across lamps Lamp 1 and Lamp 3.
That is to say, the sequence start capacitors C3 and C4 are connected from each LC resonance circuit to the series connection point of the other group of lamps. By such a way it forms an arrangement of a ballast topologies of multiple load circuits.
When the lamp Lamp 1 is broken, the coil Ll and capacitor C l will generate a very high ignition voltage due to an asymmetric circuit load.
By means of the sequence start capacitors C3 and C4, some of the current from the capacitor C l is bypassed to the capacitor C5, the voltage of the capacitor C l thus is decreased and limited, and the asymmetric resonance in the circuit is eliminated.
The same process is carried out for another lamps Lamp 2 in the same group.
When the lamp Lamp 3 is broken, the coil L2 and capacitor C2 will generate a very high ignition voltage due to an asymmetric circuit load.
By means of the sequence start capacitors C3 and C4, some of the current from the capacitor C2 is bypassed to the capacitor C5, the voltage of the capacitor C2 thus is decreased and limited, and the asymmetric resonance in the circuit is eliminated. The same process is carried out for another lamps Lamp 4 in the same group.
The ballast topologies further comprise two switches U l and U2 for connecting the resonance circuits to a power supply. For a ballast which operates in the frequency range of 2OkHz to I GGkHz, the capacitance values range of the sequence start capacitors C3 and C4 is from 14OpF to 4.9nF, the capacitance values range of the resonance capacitors C l and C2 in the LC resonance circuits can be selected from 90OpF to 16nF, and the induction values range of the coils Ll and L2 in the resonance circuits is from 950μH to 8.4mH. For a ballast which operates in the frequency range of 1 0OkHz to 500kHz, the intended capacitance values range of the sequence start capacitors C3 and C4 is from 2OpF to 90OpF, the intended capacitance values range of the resonance capacitors C l and C2 in the LC resonance circuits can be selected from 20OpF to B.όnF, and the intended induction values range of the coils L l and L2 in the resonance circuits is from l 90μH to 1.6mH.
It is understandable that the number of the lamps in the topologies is not limited to the above-mentioned embodiments. The principle of the invention can be used for any other type of fluorescent lamps and also can be extended to any number of parallel resonance circuits. A person skilled in the art could change or modify the circuit arrangement without exceeding the essence of the invention. The changes and modifications belong to the range of the invention as set forth in claims.
— ~\ —

Claims

1. A ballast circuit for running multiple fluorescent lamps of at least two fluorescent lamps, the multiple fluorescent lamps are connected in 5 series and divided into groups of every two lamps, comprising:
LC resonance circuits for igniting respective groups of the two fluorescent lamps, each of the resonance circuits is formed with a resonance capacitor (Cl; C2) and a coil (Ll ; L2) and connected between the corresponding group of the lamps and ground;
H) a DC block capacitor (C5) for conducting the electric current from the resonance capacitor (Cl ; C2) to ground, wherein the ballast circuit further comprising sequence start capacitors (C3, C4) that are connected through the filaments between both LC resonance circuits when there are two fluorescent lamps, or connected
15 from each LC resonance circuit to the connection point of the other group of lamps when there are more than two fluorescent lamps, for limiting the electric voltage generated on the respective resonance capacitor (Cl ; C2) when one of the lamps is broken in a corresponding group of fluorescent lamps. 0
2. A ballast circuit for running multiple fluorescent lamps according to claim 1, wherein the capacitance values range of the sequence start capacitors (C3, C4) is from 14OpF to 4.9nF for a ballast which operates in the frequency range of 20Id-Iz to 100kHz, and is from 2OpF to 90OpF for a ballast which operates in the frequency range of 10OkHz to 500IvHz. 5
3. A ballast circuit for running multiple fluorescent lamps according to claim 1 , wherein the capacitance values range of the resonance capacitors (Cl, C2) in the LC resonance circuits is from 90OpF to l όnF for a ballast which operates in the frequency range of 2OkHz to ! 0OkHz, and is from 20OpF to 3.6nF for a ballast which operates in the frequency range
- 6 -
1002 of 10OkHz to 50OkHz.
4. A ballast circuit for running multiple fluorescent lamps according to claim 1, wherein the induction values range of the coils (Ll , L2) in the resonance circuits is from 950μH to 8.4niH for a ballast which operates in the frequency range of 2OkHz to IQOkHz, and is from 190μH to l .όmH for a ballast which operates in the frequency range of 10OkHz to 500IcHz.
5. A ballast circuit for running multiple fluorescent lamps according to claim 1, further comprising two switches (UI , U2) for connecting the resonance circuits to a power supply.
PCT/EP2008/063565 2007-10-30 2008-10-09 A ballast circuit Ceased WO2009056431A2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP08845841A EP2206414B1 (en) 2007-10-30 2008-10-09 A ballast circuit
PL08845841T PL2206414T3 (en) 2007-10-30 2008-10-09 A ballast circuit
AT08845841T ATE538625T1 (en) 2007-10-30 2008-10-09 CIRCUIT

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN2007101657190A CN101426322B (en) 2007-10-30 2007-10-30 Ballast circuit
CN200710165719.0 2007-10-30

Publications (2)

Publication Number Publication Date
WO2009056431A2 true WO2009056431A2 (en) 2009-05-07
WO2009056431A3 WO2009056431A3 (en) 2009-07-09

Family

ID=40380569

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2008/063565 Ceased WO2009056431A2 (en) 2007-10-30 2008-10-09 A ballast circuit

Country Status (5)

Country Link
EP (1) EP2206414B1 (en)
CN (1) CN101426322B (en)
AT (1) ATE538625T1 (en)
PL (1) PL2206414T3 (en)
WO (1) WO2009056431A2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102105013A (en) * 2009-12-16 2011-06-22 奥斯兰姆有限公司 Starting-assisting device, ballast and illumination device

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5747941A (en) * 1995-12-07 1998-05-05 Energy Savings, Inc. Electronic ballast that monitors direct current through lamp filaments
US5636111A (en) * 1996-03-26 1997-06-03 The Genlyte Group Incorporated Ballast shut-down circuit responsive to an unbalanced load condition in a single lamp ballast or in either lamp of a two-lamp ballast
US6366032B1 (en) * 2000-01-28 2002-04-02 Robertson Worldwide, Inc. Fluorescent lamp ballast with integrated circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102105013A (en) * 2009-12-16 2011-06-22 奥斯兰姆有限公司 Starting-assisting device, ballast and illumination device
WO2011072982A1 (en) * 2009-12-16 2011-06-23 Osram Gesellschaft mit beschränkter Haftung Start auxiliary device, ballast and illumination device

Also Published As

Publication number Publication date
ATE538625T1 (en) 2012-01-15
CN101426322A (en) 2009-05-06
PL2206414T3 (en) 2012-08-31
CN101426322B (en) 2013-01-02
EP2206414A2 (en) 2010-07-14
WO2009056431A3 (en) 2009-07-09
EP2206414B1 (en) 2011-12-21

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