Backlight driving circuit
View Patent ↗A backlight of an LCD device includes a protection circuit that permits leakage of a high voltage to a ground terminal. This high voltage is generated by insertion failures of connectors or other failures caused by damage. The backlight driving circuit includes a high-voltage part applying an A.C. high voltage to a first terminal of a plurality of fluorescent lamps, a low-voltage part applying a lower voltage than that of the high-voltage part to a second terminal of the plurality of fluorescent lamps, a connection part that connects the high-voltage part to the low-voltage part and the protection circuit between the low-voltage part and the connection part.
1. A backlight driving circuit comprising:
a high-voltage part configured to apply an A.C. high voltage to a first terminal of a plurality of fluorescent lamps;
a low-voltage part configured to apply a lower voltage than that of the high-voltage part to a second terminal of the plurality of fluorescent lamps;
a connection part that connects the high-voltage pad to the low-voltage pad; and
a protection circuit between the low-voltage part and the connection part.
2. The backlight driving circuit of claim 1 , wherein the connection part includes first and second feedback connectors that electrically connect the high-voltage part to the low-voltage part.
3. The backlight driving circuit of claim 2 , wherein pins of the first and second feedback connectors are disposed at intervals smaller than that of a discharge distance that would permit a discharge to occur at the high and low voltages applied by the high-voltage part and low-voltage part, respectively, if insertion failures of the first and second feedback connectors existed and the protection circuit were removed.
4. The backlight driving circuit of claim 1 , wherein the protection circuit includes a plurality of zener diodes and a resistor.
5. The backlight driving circuit of claim 4 , wherein the plurality of zener diodes and the resistance are formed on a PCB (Printed Circuit Board) of the low-voltage part.
6. The backlight driving circuit of claim 4 , wherein the plurality of zener diodes are respectively connected to a power source line, between the low-voltage part and the connection part and a ground terminal in different directions and the resistor is connected between the zener diodes.
7. A backlight driving circuit comprising:
a high-voltage part at a first portion of a rear side of an LCD panel, the first high-voltage part configured to apply an AC. high voltage to a first terminal of a plurality of fluorescent lamps;
a low-voltage part at a second portion of the rear side of the LCD panel, the low-voltage part configured to apply a lower electric potential than that of the high-voltage part to a second terminal of the plurality of fluorescent lamps;
a connection part that connects the high-voltage part to the low-voltage part; and
a protection circuit through which a high voltage generated between the low-voltage part and the connection part is shunted to a ground terminal.
8. The backlight driving circuit of claim 7 , wherein the connection part includes first and second feedback connectors that electrically connect the high-voltage part to the low-voltage part.
9. The backlight driving circuit of claim 8 , wherein pins of the first and second feedback connectors are disposed at intervals smaller than that of a discharge distance that would permit a discharge to occur at the voltages applied by the high-voltage part and low-voltage part, respectively, if insertion failures of the first and second feedback connectors existed and the protection circuit were removed.
10. The backlight driving circuit of claim 7 , wherein the protection circuit includes a plurality of zener diodes and a resistor.
11. The backlight driving circuit of claim 10 , wherein the plurality of zener diodes and the resistor are formed on a PCB (Printed Circuit Board) of the low-voltage part.
12. The backlight driving circuit of claim 10 , wherein the zener diodes are respectively connected to a power source line, between the low-voltage part and the connection part, and the ground terminal in different directions and the resistor is connected between the zener diodes.
13. The backlight driving circuit of claim 7 , further comprising a direct type backlight that includes the high-voltage part, the low-voltage part, the connection part, and the protection circuit.
14. An LCD device comprising the backlight driving circuit of claim 7 .
15. A method of protecting a backlight driving circuit of an LCD device, the method comprising:
obtaining a high-voltage part and a low-voltage part that respectively supply an A.C. high voltage and a voltage lower than that of the A.C. high voltage to a plurality of fluorescent lamps;
obtaining a connection part that connects the high-voltage part and the low-voltage part; and
obtaining a protection circuit between the low-voltage part and the connection part.
16. The method of claim 15 , wherein the connection part includes first and second feedback connectors that electrically connect the high-voltage part to the low-voltage part.
17. The method of claim 16 , further comprising grounding the low-voltage part when a voltage generated between the high-voltage part and the low-voltage part is large enough to permit a discharge to occur if insertion failures of the first and second feedback connectors existed and the protection circuit were removed.
18. The method of claim 17 , wherein pins of the first and second feedback connectors are disposed at intervals smaller than that of a discharge distance over which discharge between the pins would occur.
19. The method of claim 15 , wherein the protection circuit includes a plurality of zener diodes and a resistor.
20. The method of claim 19 , wherein the plurality of zener diodes are respectively connected to a power source line, between the low-voltage part and the connection part, and a ground terminal in different directions and the resistor is connected between the zener diodes.
21. The method of claim 20 , wherein the plurality of zener diodes and the resistance are formed on a PCB (Printed Circuit Board) of the low-voltage part.
22. The method of claim 15 , further comprising applying light generated by the plurality of fluorescent lamps to a display panel of the LCD.
23. The method of claim 15 , further comprising obtaining a direct type backlight that includes the high-voltage part, the low-voltage part, the connection part, and the protection circuit.
24. The method of claim 15 , further comprising testing the protection circuit before incorporating the backlight driving circuit in the LCD device.
25. The method of claim 15 , further comprising manufacturing the backlight driving circuit.