CN1492726A - Voltage supply circuit of multiple lamp tubes - Google Patents
Voltage supply circuit of multiple lamp tubes Download PDFInfo
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- CN1492726A CN1492726A CNA021480303A CN02148030A CN1492726A CN 1492726 A CN1492726 A CN 1492726A CN A021480303 A CNA021480303 A CN A021480303A CN 02148030 A CN02148030 A CN 02148030A CN 1492726 A CN1492726 A CN 1492726A
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- transformer
- supply circuit
- siding ring
- many light
- earth point
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Abstract
This invention provides a voltage supply circuit for multiple lamps including a first and second transformers and a first and second lamps, among which, the first transformer has a primary and a secondary coils, the primary receives a first voltage signal and the first end of the secondary coil is connected to an earth point, the second transformer has a primary and a secondary coils and the heteropolarity ends of them are connected to the secone end of the first transformer secondary coil together. The first and second lamps are connected to the heteropolarity ends of the primary and secondary coils of the second transformer separately.
Description
Technical field
The present invention is particularly to a kind of voltage supply circuit of many fluorescent tubes relevant for a kind of voltage supply circuit of discharge lamp, can equiulbrium flow through each lamp tube current.
Background technology
Many displays are arranged at present, and as LCD, the fluorescent tube that all essential use is high-effect and external form is light and handy is as backlight.Cold-cathode tube (CCFL) just becomes in LCD the discharge lamp of normal use.Simultaneously, along with the size of display is increasing, backlight not applied of single fluorescent tube used, and must use a plurality of fluorescent tubes just can reach gratifying brightness in back light system.
Fig. 1 has shown the voltage supply circuit of traditional many fluorescent tubes.It has comprised a transformer 11, capacitor C 1-C3, discharge lamp 121 and 122, drive circuit 13a and feedback network 13b.The first siding ring 111 of transformer 11 receives from the low-voltage signal of 137 outputs of amplifier among the drive circuit 13a and produces a high-voltage signal in its second siding ring 112 inductions.The negativing ending grounding of the second siding ring 112 of transformer 11.Capacitor C 3 is connected in the anode of earth point and second siding ring 112.Capacitor C 1 and C2 then are connected between the anode and fluorescent tube 121 of second siding ring 112, and between second siding ring 112 anodes and the fluorescent tube 122.The other end of fluorescent tube 121,122 then is connected in feedback network 13b.Feedback network 13b has comprised diode 131,132 and resistance 133.And drive circuit 13a has comprised resistance 134,135, voltage source 135 and an amplifier 137.In drive circuit 13a, the output of amplifier 137 output low-voltage signal is to the first siding ring 111 of transformer 11.Voltage source 136 is connected between the positive input terminal and earth point of amplifier 137.Resistance 134 is connected between the negative input end of earth point and amplifier 137.Resistance 135 is connected between the negative terminal of the negative input end of amplifier 137 and diode 132.In feedback network 13b, the negative terminal of diode 131 is connected in fluorescent tube 121 and 122, and its anode then is connected to earth point.The anode of diode 132 is connected to the negative terminal of diode 131.Resistance 133 is connected between the negative terminal and earth point of diode 132.Wherein, discharge lamp 121,122 can be a cold-cathode tube.
Though above-mentioned traditional many light tube electric voltages supply circuit can use a transformer to drive fluorescent tube more than two simultaneously, being applied to can provide enough picture brightness in the back light system of display, but owing to be subjected to lead or impedance difference of fluorescent tube own or other factors, may make each lamp tube current imbalance of flowing through, and cause the brightness difference of each fluorescent tube, make the picture quality of display reduce, also may cause the lost of life of fluorescent tube simultaneously because of the electric current secundly.
Summary of the invention
In order to address the above problem, the invention provides a kind of voltage supply circuit of many fluorescent tubes, can drive a plurality of fluorescent tubes simultaneously, and make the current balance type of the fluorescent tube of flowing through.
A purpose of the present invention is to provide a kind of voltage supply circuit of many fluorescent tubes, comprise: one first transformer, have a primary side and second siding ring, this first siding ring receives one first voltage signal, and one first end of this second siding ring is connected to an earth point; One second transformer has a primary side and second siding ring, and one first polar end of this first siding ring and one second polar end of this second siding ring are connected to one second end of this first transformer secondary lateral coil jointly; And first and second fluorescent tube, be connected to one first polar end of the second siding ring of one second polar end of first siding ring of this second transformer and this second transformer respectively.
Another object of the present invention is to provide a kind of voltage supply circuit of many fluorescent tubes, comprise: a transformer, have a primary side and second siding ring, this first siding ring receives one first voltage signal, and one first end of this second siding ring is connected to an earth point; One magnetic core; One first and second coil curls up on this magnetic core, and one first polar end of this first coil and one second polar end of this second coil are connected to one second end of this transformer secondary lateral coil jointly; And first and second fluorescent tube, be connected to one second polar end of this first coil and one first polar end of this second coil respectively.
By this, utilization of the present invention provides a magnetic coupler (transformer) between two lamp tube current paths, make two lamp tube current because of magnetic couplings so, can pin down mutually and reach balance.
Below, with reference to the embodiment of description of drawings a kind of many light tube electric voltages supply circuit of the present invention.
Description of drawings
Fig. 1 has shown traditional many light tube electric voltages supply circuit;
Fig. 2 has shown the many light tube electric voltages supply circuit in the first embodiment of the invention;
Fig. 3 has shown the many light tube electric voltages supply circuit in the second embodiment of the invention.
Symbol description
11,21,31,32: transformer;
111,112,211,212: coil;
213: magnetic core;
121,122: discharge lamp;
13a, 13b: drive circuit;
13b, 33b: feedback network;
131,132,138,139: diode;
133,134,135,140,141: resistance;
136: voltage source;
137: amplifier;
C1-C6: electric capacity.
Embodiment
Fig. 2 has shown the many light tube electric voltages supply circuit in one embodiment of the invention.For illustrative simplicity, assembly identical among Fig. 2 and Fig. 1 uses identical symbol.It has comprised transformer 11 and 21, capacitor C 1-C3, discharge lamp 121 and 122, drive circuit 13a and a feedback network 13b.The first siding ring 111 of transformer 11 receives a low-voltage signal from drive circuit 13a, and the negative terminal of its second siding ring 112 is connected to earth point.Transformer 21 has one lateral coils 211 and second siding ring 212 curls up on same magnetic core 213, and the winding turns with similar number, the heteropolarity end (positive and negative end) of primary side and second siding ring 211,212 is connected to the anode of the second siding ring of this transformer 11 jointly via capacitor C 1 and C2.Fluorescent tube 121,122 is connected to the anode of the second siding ring 212 of the negative terminal end of first siding ring 211 of transformer 21 and transformer 21 respectively.Capacitor C 3 is connected between the anode and earth point of second siding ring 112 of transformer 11.Capacitor C 1 is connected in the anode of the first siding ring 211 of the anode of second siding ring 112 of this transformer 11 and transformer 21.Capacitor C 2 is connected in the negative terminal of the second siding ring 212 of the anode of second siding ring 112 of transformer 11 and transformer 21.Feedback network 13b has comprised diode 131,132 and resistance 133.And drive circuit 13a has comprised resistance 134,135, voltage source 135 and an amplifier 137.In drive circuit 13a, the output of amplifier 137 output low-voltage signal is to the first siding ring 111 of transformer 11.Voltage source 136 is connected between the positive input terminal and earth point of amplifier 137.Resistance 134 is connected between the negative input end of earth point and amplifier 137.Resistance 135 is connected between the negative terminal of the negative input end of amplifier 137 and diode 132.In feedback network 13b, the negative terminal of diode 131 is connected in fluorescent tube 121 and 122, and its anode then is connected to earth point.The anode of diode 132 is connected to the negative terminal of diode 131.Resistance 133 is connected between the negative terminal and earth point of diode 132.Wherein, discharge lamp 121,122 can be a cold-cathode tube.
In the above-described embodiment, utilized transformer 21 to respond to fluorescent tube 121,122 electric current, utilize faraday's (Faraday) law and ampere (Ampere) law, as the bigger side of electric current, positive induced electromotive force will be produced, otherwise then produce negative induced electromotive force, for example when the electric current I 1 of fluorescent tube 121 during greater than the electric current I 2 of fluorescent tube 122, primary side at transformer 21 will produce a positive induced voltage, and produce a negative induced voltage at the secondary side of transformer 21, thus, electric current I 1 will reduce because of the generation of positive induced electromotive force, electric current I 2 will increase because of the generation of negative induced electromotive force, makes two electric currents tend to be balanced.
In addition, in the above-described embodiment, transformer 11 can be two-wire system transformer or center-tapped transformer, and capacitor C 3 can also selectivity be used, and drive circuit 13a and feedback network 13b can also have and be different from circuit structure shown in Figure 2.
Fig. 3 has shown the many light tube electric voltages supply circuit in the second embodiment of the invention.It has comprised transformer 11,21,31,32, capacitor C 1-C6, discharge lamp 121-124, drive circuit 33a and a feedback network 33b.With Fig. 2 relatively under, as can be seen, the many light tube electric voltages supply circuit among Fig. 3 has used a transformer 31 in parallel with transformer 11, additionally promotes other two fluorescent tubes 123 and 124.Between the current path of fluorescent tube 123 and 124, also be provided with a transformer 32 reaches balanced balanced current to realize a magnetic couplings mechanism purpose.Feedback network 33b has then comprised diode 131,132,138,139 and resistance 133,141.Drive circuit 33a has then comprised voltage source 136, resistance 140,134,135 and amplifier 137.In feedback network 33b,, also additionally used diode 138,139 and resistance 140,141 to increase by a feedback paths for the fluorescent tube 123 and 124 that cooperates increase.So, just, can finish a voltage supply circuit that can promote four fluorescent tubes.Wherein, discharge lamp 121-124 can be a cold-cathode tube.
In like manner, in above-mentioned second embodiment, can also continue transformer in parallel more, and between two lamp current paths that each transformer promotes, provide another transformer to make current balance type, can finish the voltage supply circuit that can promote six, eight, ten or the like more fluorescent tubes.
Comprehensively above-mentioned, the invention provides a kind of voltage supply circuit of many fluorescent tubes, utilization provides a magnetic coupler (transformer) between two lamp tube current paths, by utilize Faraday's law and Ampere's law make two lamp tube current because of magnetic couplings so pin down mutually, tend to be balanced at last.So, just can avoid in traditional many light tube electric voltages supply circuit,, make the picture brightness inequality of display because of current imbalance, or the shortcoming that shortens of lamp tube service life.
Though the present invention with a preferred embodiment openly as above; right its is not in order to limit the present invention; any those skilled in the art; under the situation that does not break away from the spirit and scope of the present invention; can change and improvement, so protection scope of the present invention is as the criterion with the claim restricted portion that is proposed.
Claims (18)
1. the voltage supply circuit of fluorescent tube more than a kind comprises:
One first transformer has a primary side and second siding ring, and this first siding ring receives one first voltage signal, and one first end of this second siding ring is connected to an earth point;
One second transformer has a primary side and second siding ring, and one first polar end of this first siding ring and one second polar end of this second siding ring are connected to one second end of this first transformer secondary lateral coil jointly; And
One first and second fluorescent tube is connected to one first polar end of the second siding ring of one second polar end of first siding ring of this second transformer and this second transformer respectively.
2. many light tube electric voltages supply circuit as claimed in claim 1, wherein this fluorescent tube is a discharge lamp.
3. many light tube electric voltages supply circuit as claimed in claim 2, wherein this discharge lamp is a cold-cathode tube.
4. many light tube electric voltages supply circuit as claimed in claim 1 wherein also comprises:
One first electric capacity is connected between second end and this earth point of second siding ring of this first transformer;
One second electric capacity is connected between first polar end of first siding ring of second end of second siding ring of this first transformer and this second transformer; And
One the 3rd electric capacity is connected between second polar end of second siding ring of second end of second siding ring of this first transformer and this second transformer.
5. many light tube electric voltages supply circuit as claimed in claim 1 wherein also comprises an one drive circuit and a feedback network, is series between this first and second fluorescent tube and this first transformer.
6. many light tube electric voltages supply circuit as claimed in claim 5, wherein this drive circuit comprises:
One amplifier has an output and exports this first voltage signal;
One voltage source is connected between the positive input terminal and an earth point of this amplifier;
One first resistance is connected between the negative input end of this earth point and this amplifier; And
One second resistance is connected between the negative input end and this feedback network of this amplifier.
7. many light tube electric voltages supply circuit as claimed in claim 5, wherein this feedback network comprises:
One first diode has a negative terminal and be connected in this first and second fluorescent tube, and an anode is connected to this earth point;
One second diode, its anode is connected to the negative terminal of this first diode, and negative terminal is connected to this drive circuit; And
One resistance is connected between the negative terminal and this earth point of this second diode.
8. many light tube electric voltages supply circuit as claimed in claim 1, wherein this first polar end is an anode, this second polar end is a negative terminal.
9. many light tube electric voltages supply circuit as claimed in claim 1, wherein the primary side of this second transformer and second siding ring have identical winding turns.
10. the voltage supply circuit of fluorescent tube more than a kind comprises:
One transformer has a primary side and second siding ring, and this first siding ring receives one first voltage signal, and one first end of this second siding ring is connected to an earth point;
One magnetic core;
One first and second coil curls up on this magnetic core, and one first polar end of this first coil and one second polar end of this second coil are connected to one second end of this transformer secondary lateral coil jointly; And
One first and second fluorescent tube is connected to one second polar end of this first coil and one first polar end of this second coil respectively.
11. many light tube electric voltages supply circuit as claimed in claim 10, wherein this fluorescent tube is a discharge lamp.
12. many light tube electric voltages supply circuit as claimed in claim 11, wherein this discharge lamp is a cold-cathode tube.
13. many light tube electric voltages supply circuit as claimed in claim 10 wherein also comprises:
One first electric capacity is connected between second end and this earth point of second siding ring of this transformer;
One second electric capacity is connected between first polar end of second end of second siding ring of this transformer and this first coil; And
One the 3rd electric capacity is connected between second polar end of second end of second siding ring of this transformer and this second coil.
14. many light tube electric voltages supply circuit as claimed in claim 10 wherein also comprises an one drive circuit and a feedback network, is series between this first and second fluorescent tube and this transformer.
15. many light tube electric voltages supply circuit as claimed in claim 14, wherein this drive circuit comprises:
One amplifier has an output and exports this first voltage signal;
One voltage source is connected between the positive input terminal and an earth point of this amplifier;
One first resistance is connected between the negative input end of this earth point and this amplifier; And
One second resistance is connected between the negative input end and this feedback network of this amplifier.
16. many light tube electric voltages supply circuit as claimed in claim 14, wherein this feedback network comprises:
One first diode has a negative terminal and be connected in this first and second fluorescent tube, and an anode is connected to this earth point;
One second diode, its anode is connected to the negative terminal of this first diode, and negative terminal is connected to this drive circuit; And
One resistance is connected between the negative terminal and this earth point of this second diode.
17. many light tube electric voltages supply circuit as claimed in claim 10, wherein this first polar end is an anode, and this second polar end is a negative terminal.
18. many light tube electric voltages supply circuit as claimed in claim 10, wherein this first and second coil has identical winding turns.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021480303A CN100346670C (en) | 2002-10-21 | 2002-10-21 | Voltage supply circuit of multiple lamp tubes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021480303A CN100346670C (en) | 2002-10-21 | 2002-10-21 | Voltage supply circuit of multiple lamp tubes |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1492726A true CN1492726A (en) | 2004-04-28 |
| CN100346670C CN100346670C (en) | 2007-10-31 |
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ID=34233079
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021480303A Expired - Fee Related CN100346670C (en) | 2002-10-21 | 2002-10-21 | Voltage supply circuit of multiple lamp tubes |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100346670C (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2340145Y (en) * | 1998-05-07 | 1999-09-22 | 鸿友科技股份有限公司 | Power-supply control apparatus for cold-cathode fluorescent lamp tube |
| US6104146A (en) * | 1999-02-12 | 2000-08-15 | Micro International Limited | Balanced power supply circuit for multiple cold-cathode fluorescent lamps |
-
2002
- 2002-10-21 CN CNB021480303A patent/CN100346670C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN100346670C (en) | 2007-10-31 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20071031 Termination date: 20121021 |