GB2522699A - Lighting Unit and Driver circuit - Google Patents
Lighting Unit and Driver circuit Download PDFInfo
- Publication number
- GB2522699A GB2522699A GB1401845.1A GB201401845A GB2522699A GB 2522699 A GB2522699 A GB 2522699A GB 201401845 A GB201401845 A GB 201401845A GB 2522699 A GB2522699 A GB 2522699A
- Authority
- GB
- United Kingdom
- Prior art keywords
- lighting unit
- inductance
- ground
- driver circuit
- circuit according
- 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.)
- Pending
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
- H05B41/282—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
- H05B41/2825—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 by means of a bridge converter in the final stage
-
- 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
- H05B41/282—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
- H05B41/2825—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 by means of a bridge converter in the final stage
- H05B41/2828—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 by means of a bridge converter in the final stage using control circuits for the switching elements
Landscapes
- Circuit Arrangements For Discharge Lamps (AREA)
Abstract
A lighting unit and driver circuit 1 includes a lighting unit 10 having first and second terminals 10a,10b, first and second current limiting inductances 11a,11b connected to the first and second terminals respectively, a first pulsing means 20 to deliver a first pulsed power supply through the first inductance, lighting unit, and second inductance to ground, a second pulsing means 30 to deliver a second pulsed power supply through the second inductance, lighting unit, and first inductance to ground, alternating means to alternate between the first or second pulsing means driving the lighting unit and first and second inductances , and timing means to generate a dead period of time between the delivery of the first and second pulsed power supplies and to connect the first inductance, lighting unit and second inductance to ground, whereby to dissipate power stored in the inductances.
Description
TITLE: Lighting Unit and Driver Circuit The present invention relates to a lighting unit and driver circuit, especially for units such as fluorescent tubes and LEDs.
It is known to drive a fluorescent tube using a circuit sometime called a ballast. This ballast supplies a pulsed DC waveform through a current limiting inductance to an electrode at one end of a tube, with the electrode at the other end of the tube being connected to ground. The pulses are delivered through a pair of square wave-driven Mosfets which are sequentially tuned on and off to each deliver alternate pulses of power.
Between pulses provided by the Mosfets is a period of dead time in which energy in the inductance is stored and wasted in switching losses. This leads to power losses making the ballast circuit inefficient.
An example of such a ballast and its waveform is given in Figure 1.
The invention seeks to provide a circuit which overcomes the disadvantages of this known circuit, and which may further be used to dim lighting units.
According to the present invention there is provided a lighting unit and driver circuit comprising: a) a lighting unit having first and second terminals, b) a first and second current limiting inductances connected to first and second terminals respectively, c) a first pulsing means to deliver a first pulsed power supply through the first inductance, lighting unit, and second inductance to ground d) a second pulsing means to deliver a second pulsed power supply through the second inductance, lighting unit, and first inductance to ground, e) alternating means to alternate between the first or second pulsing means being delivered to the lighting unit and first and second inductances, and f) timing means to generate dead period of time between first and second pulsed power supplies and to connect the first inductance, lighting unit and second inductance to ground, whereby to dissipate power stored in the first and second inductances.
Preferably the lighting unit is a fluorescent tube or diodes. The diodes may be an array of diodes in a bridge to allow current flow in both directions between first and second terminals.
Preferably the first pulsing means is provided by a pair of Mosfets driven by a square wave.
Preferably the second pulsing means is provided by a pair of Mosfets driven by a square wave.
Preferably one of each of said pairs is connected to ground whereby the Mosfet of the second pulsing means connected to ground connects the second inductance to ground and the Mosfet of the first pulsing means connected to ground connects the first inductance to ground.
Preferably the timing means isolates the inductors and lighting unit before and after connecting the first inductance, lighting unit and second inductance to ground.
Preferably the timing means is adjustable to adjust the length of the dead time to control the amount of power delivered to the lighting unit whereby to dim or brighten the lighting unit.
An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 2 shows a fluorescent tube and a schematic circuit, Figure 3 shows an additional circuit to drive the circuit of Figure 2, Figure 4 shows a trace of the pulsed power supplies and the dead time, FigureS shows a the effect of adjusting the timing means to dim a lighting unit, and Figure 6 shows an LED array as an alternative to the fluorescent tube.
Referring to Figure 2 there is shown a lighting unit and driver circuit 1.
A lighting unit in the form of a fluorescent tube 10 is provided having first and second terminals 1 OA, 1 (lB.
A first and second current limiting inductances 1 IA,1 lB are connected in series to first and second tenninals 1OA,1OB respectively.
A first pulsing means in the form of driver 20 is provided to deliver a first pulsed power supply through the first inductance 1 1A, lighting unit 10, and second inductance 1 lB to ground B. Driver 20 has a pair of mosfets 21,22 driven by a square wave.
A second pulsing means in the form of driver 30 is provided to deliver a second pulsed power supply through the second inductance 1 lB. lighting unit 10, and first inductance 1 IA to ground B. Driver 30 has a pair of mosfets 31,32 driven by a square wave.
Mosfet 21,31 are connected to ground whereby the Mosfet 31 of the second pulsing means connected to ground connects the second inductance 1 lB to ground and the Mosfet 22 of the first pulsing means connected to ground connects the first inductance I lÀ to ground.
Drivers 20,30 include an alternating means to alternate between the first or second pulsing means being delivered to the lighting unit and first and second inductances, and timing means to generate dead period of time between first and second pulsed power supplies and to connect the first inductance, lighting unit and second inductance to ground, whereby to dissipate power stored in the first and second inductances.
Drivers 20,30 may be controlled by the circuit of Figure 3, the output Q1,Q2 of which control driver 20, and the output Q3,Q4 of which control driver 30.
Referring now to Figure 4, there is shown the voltage and current waveforms delivered by the first and second pulsing means.
As shown by the waveform section for period Ti, Mosfets 21 and 32 go on (with Mosfets 22,31 off) allowing current to flow from Mosfet 21, through inductance 1 IA, tube 10, inductance 1 lB, through Mosfet 32 to ground.
As shown for waveform period 12, for a first period T2A all the Mosfets are off and no current flows (isolating the inductors I 1,11 B and tube 10). Then for a second period T2B Mosfets 22,32 go on to connect the first inductance, lighting unit and second inductance to ground, whereby to dissipate power stored in the first and second inductances. For a third period T2C all the Mosfets are off and no current flows (isolating the inductors 1 1A,1 lB and tube 10).
As shown by the waveform section for period T3, Mosfets 31 and 22 go on (with Mosfets 2 1,32 off) allowing current to flow from Mosfet 31, through inductance 1 1B, tube 10, inductance 1 1A, through Mosfet 22 to ground.
As shown for waveform period 14, for a first period T4A all the Mosfets are off and no current flows (isolating the inductors 1 1,11 B and tube 10). Then for a second period T4B Mosfets 22,32 go on to connect the first inductance, lighting unit and second inductance to ground, whereby to dissipate power stored in the first and second inductances. For a third period T4C all the Mosfets are off and no current flows (isolating the inductors 1 1A,l lB and tube 10).
This cycle repeats itself.
Pulsing of the tube 10 does not flash the tube because the decay time of the light emitted by the gases in the tube is too long. It has been found that is the time T2 or 14 is extended as shown in Figure 5, then the tube will appear dim. Adjusting the length of the dead time controls the amount of power delivered to the lighting unit whereby to dint or brighten the lighting unit as required.
The circuit shown may be used to power other types of lighting units in addition to fluorescent Tubes. One such unit may be an array of diodes 40A,40B in a bridge to allow current flow in both directions between first and second terminals 41A,41B as shown in Figure 6.
The invention may take a form different to that specifically described above.
Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.
Claims (9)
- SCLAIMS1. A lighting unit and driver circuit comprising: a) a lighting unit having first and second terminals, b) a first and second current limiting inductances connected to first and second terminals respectively, c) a first pulsing means to deliver a first pulsed power supply through the first inductance, lighting unit, and second inductance to ground, d) a second pulsing means to deliver a second pulsed power supply through the second inductance, lighting unit, and first inductance to ground, e) alternating means to alternate between the first or second pulsing means being delivered to the Lighting unit and first and second inductances, and f) timing means to generate dead period of time between first and second pulsed power supplies and to connect the first inductance, lighting unit and second inductance to ground, whereby to dissipate power stored in the first and second inductances.
- 2. A lighting unit and driver circuit according to claim 1, wherein the lighting unit is a fluorescent tube or diodes.
- 3. A lighting unit and driver circuit according to claim 2, wherein the diodes may be an array of diodes in a bridge to allow current flow in both directions between first and second terminals.
- 4. A lighting unit and driver circuit according to any preceding claim, wherein the first pulsing means is provided by a pair of Mosfets driven by a square wave.
- 5. A lighting unit and driver circuit according to any preceding claim, wherein the second pulsing means is provided by a pair of Mosfets driven by a square wave.
- 6. A lighting unit and driver circuit according to claim 4 and 5, wherein one of each of said pairs is connected to ground whereby the Mosfet of the second pulsing means connected to ground connects the second inductance to ground and the Mosfet of the first pulsing means connected to ground connects the first inductance to ground.
- 7. A lighting unit and driver circuit according to any preceding claim, wherein the timing means isolates the inductors and lighting unit before and after connecting the first inductance, lighting unit and second inductance to ground.
- 8. A lighting unit and driver circuit according to any preceding claim, wherein the timing means is adjustable to adjust the length of the dead time to control the amount of power delivered to the lighting unit whereby to dim or brighten the lighting unit.
- 9. A lighting unit and driver circuit substantially as hereinbefore described with reference to and as shown in Figures 2 to 6 of the accompanying drawings.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1401845.1A GB2522699A (en) | 2014-02-04 | 2014-02-04 | Lighting Unit and Driver circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1401845.1A GB2522699A (en) | 2014-02-04 | 2014-02-04 | Lighting Unit and Driver circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
GB201401845D0 GB201401845D0 (en) | 2014-03-19 |
GB2522699A true GB2522699A (en) | 2015-08-05 |
Family
ID=50344325
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1401845.1A Pending GB2522699A (en) | 2014-02-04 | 2014-02-04 | Lighting Unit and Driver circuit |
Country Status (1)
Country | Link |
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GB (1) | GB2522699A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2562258A (en) * | 2017-05-09 | 2018-11-14 | Quintet Electronic Patents Ltd | Pulse width modulated voltage regulator |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020190665A1 (en) * | 2001-06-15 | 2002-12-19 | Matsushita Electric Works R&D Laboratory, Inc. | Apparatus and method for driving a high intensity discharge lamp |
US20050035722A1 (en) * | 2003-08-11 | 2005-02-17 | Patent-Treuhand-Gesellschaft Fur Elektrisch Gluhlampen Mbh | Electronic ballast for a lamp to be operated with iterative voltage pulses |
US20050035724A1 (en) * | 2002-01-02 | 2005-02-17 | Peter Lurkens | Electronic circuit, and method of operating a high-pressure lamp |
US20070018590A1 (en) * | 2005-07-20 | 2007-01-25 | Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh | Circuit arrangement having a converter without a transformer but with an inductor for the pulsed operation of dielectric barrier discharge lamps |
-
2014
- 2014-02-04 GB GB1401845.1A patent/GB2522699A/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020190665A1 (en) * | 2001-06-15 | 2002-12-19 | Matsushita Electric Works R&D Laboratory, Inc. | Apparatus and method for driving a high intensity discharge lamp |
US20050035724A1 (en) * | 2002-01-02 | 2005-02-17 | Peter Lurkens | Electronic circuit, and method of operating a high-pressure lamp |
US20050035722A1 (en) * | 2003-08-11 | 2005-02-17 | Patent-Treuhand-Gesellschaft Fur Elektrisch Gluhlampen Mbh | Electronic ballast for a lamp to be operated with iterative voltage pulses |
US20070018590A1 (en) * | 2005-07-20 | 2007-01-25 | Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh | Circuit arrangement having a converter without a transformer but with an inductor for the pulsed operation of dielectric barrier discharge lamps |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2562258A (en) * | 2017-05-09 | 2018-11-14 | Quintet Electronic Patents Ltd | Pulse width modulated voltage regulator |
Also Published As
Publication number | Publication date |
---|---|
GB201401845D0 (en) | 2014-03-19 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) | ||
S20A | Reinstatement of application (sect. 20a/patents act 1977) |
Free format text: REQUEST FOR REINSTATEMENT FILED Effective date: 20170307 |