Apparatus for driving lamp of liquid crystal display device
View Patent ↗The present invention relates to a lamp driving apparatus of a liquid crystal display capable of simplifying a structure of the liquid crystal display and in addition preventing a leakage current of the lamp driving apparatus. The lamp driving apparatus of the liquid crystal display comprises a plurality of lamps, and an inverter block having a plurality of inverters that supply a drive current to the lamps wherein adjacent lamps have a different phase from one another.
1. A lamp driving apparatus of a liquid crystal display, comprising:
a plurality of lamps; and
an inverter block having a plurality of transformers that convert a voltage from a voltage source into a drive current and supply the current to the plurality of lamps wherein a primary winding and a secondary winding of the transformers that supply current to the odd-numbered lamps are wound in the same direction and a primary winding and a secondary winding of the transformers that supply current to the even-numbered lamps are wound in the opposite direction from each other such that the odd-numbered lamps have a different phase from the even-numbered lamps.
2. The lamp driving apparatus of the liquid crystal display according to claim 1 , further comprising a current detector block that detects the lamp drive current supplied to each of the plurality of lamps from the inverter block.
3. The lamp driving apparatus of the liquid crystal display according to claim 2 , wherein the inverter block further comprises:
a plurality of switching circuits that switch the voltage into the plurality of transformers; and
a plurality of controllers controlling the switching circuits with reference to a feedback signal from the current detector block.
4. The lamp driving apparatus of the liquid crystal display according to claim 3 , wherein the current detector block is connected to the secondary windings of the transformers.
5. The lamp driving apparatus of the liquid crystal display according to claim 3 , wherein the current detector block includes a plurality of current detectors, each current detector within the current detector block comprising:
a resistor connected between the secondary winding of a transformer and a ground voltage source;
a first diode connected between a control block and a first node between the secondary winding of the transformer and the resistor;
a variable resistor connected between the ground voltage source and a node between the first diode and the control block; and
a capacitor connected in parallel to the variable resistor.
6. The lamp driving apparatus of the liquid crystal display according to claim 5 , wherein each of the current detectors in the current detector block further comprises:
a second diode connected between the ground voltage source and the node between the first node and the first diode.
7. The lamp driving apparatus of the liquid crystal display according to claim 2 , further comprising an integrated circuit substrate on which the inverter block and current detector block are mounted, the integrated circuit substrate being folded towards a rear surface of the liquid crystal display.
8. The lamp driving apparatus of the liquid crystal display according to claim 1 , further comprising:
a first common line commonly connected to a second electrode terminal of each odd-numbered lamp of the plurality of lamps;
a second common line commonly connected to a second electrode terminal of each even-numbered lamp of the plurality of lamps; and
a ground voltage line connecting the first common line and the second common line to a ground voltage source.
9. A lamp driving apparatus of a liquid crystal display, comprising:
a plurality of lamps including a plurality of odd-numbered lamps and a plurality of even-numbered lamps; and
an inverter block having a first plurality of transformers that convert a voltage from a voltage source into a drive current and supply the drive current to the plurality of lamps, wherein the plurality of transformers that supply the drive current to the even-numbered lamps have a first phase and the plurality of transformers that supply the drive current to the odd-numbered lamps have a phase opposite the first phase; and
wherein a primary winding and a secondary winding of the transformers that supply current to the odd-numbered lamps are wound in the same direction and a primary winding and a secondary winding of the transformers that supply current to the even-numbered lamps are wound in the opposite direction from each other.
10. The lamp driving apparatus of the liquid crystal display according to claim 9 , further comprising a current detector block that detects the lamp drive current supplied to each of the plurality of lamps from the inverter block.
11. The lamp driving apparatus of the liquid crystal display according to claim 10 , further comprising an integrated circuit substrate on which the inverter block and current detector block are mounted, the integrated circuit substrate being folded towards a rear surface of the liquid crystal display.
12. The lamp driving apparatus of the liquid crystal display according to claim 10 , wherein the inverter block comprises:
a plurality of switching circuits that switch the voltage into the plurality of transformers; and
a plurality of controllers controlling the switching circuits with reference to a feedback signal from the current detector block.
13. The lamp driving apparatus of the liquid crystal display according to claim 12 , wherein the current detector block is connected to the secondary windings of the transformers.
14. The lamp driving apparatus of the liquid crystal display according to claim 12 , wherein each current detector in the current detector block comprises:
a resistor connected between a secondary winding of the transformer and a ground voltage source;
a first diode connected between a control block and a first node between the secondary winding of the transformer and the resistor;
a variable resistor connected between the ground voltage source and a node between the first diode and the control block; and
a capacitor connected in parallel to the variable resistor.
15. The lamp driving apparatus of the liquid crystal display according to claim 14 , wherein each current detector in the current detector block further comprises a second diode connected between the ground voltage source and the node between the first node and the first diode.
16. The lamp driving apparatus of the liquid crystal display according to claim 9 , further comprising:
a first common line commonly connected to a second electrode terminal of each odd-numbered lamp of the plurality of lamps;
a second common line commonly connected to a second electrode terminal of each even-numbered lamp of the plurality of lamps; and
a ground voltage line connecting the first common line and the second common line to a ground voltage source.