Inverter for setting initial driving frequency for a liquid crystal display and driving method thereof

1. An inverter for a liquid crystal display comprising:

a DC/AC converting unit that converts DC power supplied from a voltage source into AC power;

a transformer that converts the AC power supplied from the DC/AC converting unit into a high voltage AC; and

a frequency controller that is connected to the DC/AC converting unit to control the frequency of an output of the DC/AC converting unit such that the output of the DC/AC converting unit has an initial driving frequency during an initial driving time when initiating driving of a liquid crystal panel and such that the output of the DC/AC converting unit has a normal driving frequency larger than the initial driving frequency after the initial driving time,

wherein the frequency controller includes:

a first resistor having one end connected with a power source voltage;

a first capacitor formed between the other end of the first resistor and a ground potential source:

a transistor having a base connected to a node between the first resistor and the first capacitor and an emitter connected the ground potential source;

a second resistor connected between a collector of the transistor and a first input terminal of the DC/AC converting unit; and

a third resistor having one end connected with the first input terminal of the DC/AC converting unit and the other end connected with a ground potential source, wherein the transistor upon turning on connects the third resistor in parallel with the second resistor.

2. The inverter of claim 1 , further comprising:

a second capacitor connected between a second input terminal of the DC/AC converting unit and a ground potential source.

3. The inverter of claim 2 , wherein upon applying an initial driving voltage the transistor is maintained in a turned-off state during an initial driving time beginning upon application of the initial driving voltage, the duration of the initial driving time determined by the first resistor and the first capacitor, and wherein the initial driving frequency is determined by the third resistor and the second capacitor during the initial driving time.

4. The inverter of claim 2 , wherein the transistor is turned on during a normal driving time that follows the initial driving time, and the normal driving frequency is determined by the second resistor, the third resistor, and the second capacitor.

5. The inverter of claim 1 , wherein the transistor is a bipolar junction transistor (BJT).

6. The inverter of claim 1 , wherein the inverter further comprises a feedback circuit unit that detects a feedback signal from a lamp connected to a secondary side of the transformer and supplies the feedback signal to the DC/AC converting unit.

7. The inverter of claim 6 , wherein the feedback signal is a tube current supplied to the lamp.

8. A method for driving an inverter for a liquid crystal display, comprising:

converting DC power supplied to an input terminal into AC power;

converting the AC power into a high voltage AC and outputting the same;

controlling the converting DC power supplied to the input terminal into AC power such that the AC power has an initial driving frequency during an initial driving; and

controlling the converting DC power supplied to the input terminal into AC power such that the AC power has a normal driving frequency larger than the initial driving frequency during a normal driving that follows the initial driving,

wherein the controlling the converting DC power supplied to the input terminal into AC power such that the AC power has the initial driving frequency during the initial driving and the controlling the converting DC power supplied to the input terminal into AC power such that the AC power has the normal driving frequency larger than the initial driving frequency during the normal driving that follows the initial driving are performed by a frequency controller,

wherein the frequency controller comprises:

a first resistor having one end connected with a power source voltage;

a first capacitor connected between the other end of the first resistor and a ground potential source;

a transistor having a base connected to a node between the first resistor and the first capacitor, and an emitter connected to a ground potential source;

a second resistor connected between a collector of the transistor and a first input terminal of a DC/AC converting unit; and

a third resistor having one end connected with a first input terminal of the DC/AC converting unit and the other end connected with a ground potential source, so as to be connected in parallel with the second resistor upon turning on the transistor.

9. The method of claim 8 , wherein, the controlling the converting DC power supplied to the input terminal into AC power such that the AC power has the initial driving frequency during the initial driving includes maintaining the transistor in a turned-off state during an initial driving time having a duration determined by the first resistor and the first capacitor, and determining the initial driving frequency using the third resistor and the second capacitor during the initial driving time.

10. The method of claim 8 , wherein in controlling the converting DC power supplied to the input terminal into AC power such that the AC power has the normal driving frequency larger than the initial driving frequency during the normal driving that follows the initial driving, the transistor is turned on during the normal driving that follows the initial driving, and the normal driving frequency is determined by the second resistor, the third resistor, and the second capacitor that are connected in parallel.

11. The method of claim 8 , further comprising:

detecting a feedback signal from a lamp that provides a light source; and

controlling a voltage of the high voltage AC according to the feedback signal.