Backlight driving system for liquid crystal display
There is provided a backlight driving system for a liquid crystal display that can reduce size and weight of a product because a DC-DC converter is not used when commercial AC power is converted into lamp driving power. A backlight driving system for a liquid crystal display according to an aspect of the invention includes a power supply unit converting commercial alternating current (AC) power into direct current (DC) power having a voltage level set beforehand, an inverter unit converting the DC power from the power supply unit into AC power at a one-to-one conversion ratio set beforehand, a boosting unit boosting the AC power from the inverter unit into lamp lighting power set beforehand; and a lamp group receiving the lamp lighting power from the boosting unit to emit light.
1. A backlight driving system for a liquid crystal display, the system comprising:
a power supply unit for converting first alternating current (AC) power into direct current (DC) power having a voltage level;
an inverter unit for converting the DC power from the power supply unit into second AC power at a one-to-one conversion ratio;
a boosting unit for boosting the second AC power from the inverter unit into lamp lighting power; and
at least one lamp for receiving the lamp lighting power from the boosting unit to emit light,
wherein the inverter unit comprises:
a switch for switching the DC power transmitted from the power supply unit; and
a one-to-one transformer having a one-to-one winding ratio corresponding to the one-to-one voltage conversion ratio for converting the power switched by the switch into AC power having substantially the same voltage level as the voltage level of the DC power.
2. The system of claim 1 , wherein
the power supply unit comprises:
an electromagnetic interference (EMI) suppression filter for removing electromagnetic interference of the first AC power;
a rectifier for smoothing and rectifying the first AC power through the EMI suppression filter; and
a power factor corrector for performing power factor correction of the first AC power rectified by the rectifier to convert the corrected first AC power to the DC power, and
the boosting unit comprises a distribution transformer converting the second AC power from the one-to-one transformer to the lamp lighting power and distributing the lamp lighting power to at least one lamp.
3. The system of claim 2 , further comprising:
a first board having a first mounting region and a second board physically separated from the first board and having a second mounting region,
wherein the power supply unit and the inverter unit are mounted on the first mounting region of the first board, and the boosting unit is mounted on the second mounting region of the second board.
4. The system of claim 3 , wherein the system further comprises a cable connecting the one-to-one transformer with the distribution transformer.
5. The system of claim 3 , wherein the distribution transformer is a one-to-one distribution transformer for transmitting the lamp lighting power to one of the at least one lamp or a one-to-many distribution transformer for transmitting the lamp lighting power to at least two lamps.
6. The system of claim 3 , wherein the switch of the inverter is a full-bridge switch, a half-bridge switch, or a push-pull switch.
7. The system of claim 3 , wherein the first board comprises a primary ground having a first ground region and a secondary ground having a second ground region isolated from the first ground region of the primary ground, and
the EMI suppression filter, the rectifier, the power factor corrector, the switch, and a primary side of the one-to-one transformer are grounded to the primary ground, and a secondary side of the one-to-one transformer is grounded to the secondary ground.
8. The system of claim 1 , wherein the at least one lamp comprises at least one external electrode fluorescent lamp.
9. The system of claim 8 , wherein
the power supply unit comprises:
an electromagnetic interference (EMI) suppression filter for removing electromagnetic interference from the AC power;
a rectifier for smoothing and rectifying the first AC power through the EMI suppression filter; and
a power factor corrector for performing power factor correction of the first AC power rectified by the rectifier to convert the corrected first AC power into the DC power, and
the boosting unit comprises a distribution transformer for converting the second AC power from the one-to-one transformer to the lamp lighting power to distribute the lamp lighting power to the at least one lamp.
10. The system of claim 9 , wherein the distribution transformer is a one-to-one distribution transformer for transmitting the lamp lighting power to the one external electrode fluorescent lamp or a one-to-many distribution transformer for transmitting the lamp lighting power to at least two external electrode fluorescent lamps.
11. The system of claim 9 , wherein the switch of the inverter unit is a full-bridge switch, a half-bridge switch, or a push-pull switch.