Backlight unit controlling current to light source unit and display apparatus having the same

摘要

A backlight unit includes light source units which emit light, and light source driving integrated circuits which control a brightness of the light source units, respectively. Each of the light source driving integrated circuits includes a current generator which generates a first current and a second current, a current level controller which controls a current value of the first current in response to duty ratio information of a pulse width modulation signal, a voltage supply unit which outputs a voltage corresponding to the second current, an output buffer unit which outputs the voltage from the voltage supply unit, and a driving switch unit which drives the light source units to allow a current corresponding to the voltage provided from the output buffer unit to flow through the light source units, where current values of the second current and the first current are the same as each other.

主权项

1. A backlight unit comprising:
a plurality of light source units which emits light; and a plurality of light source driving integrated circuits which controls a brightness of the light source units, respectively, wherein each of the light source driving integrated circuits comprises:
a current generator which generates a first current and a second current;a current level controller which controls a current value of the first current in response to duty ratio information of a pulse width modulation signal;a voltage supply unit which outputs a voltage corresponding to the second current;an output buffer unit which outputs the voltage provided from the voltage supply unit and maintained in a turned-on state without being repeatedly turned on and off; anda driving switch unit which drives the light source units to allow a current corresponding to the voltage provided from the output buffer unit to flow through the light source units, and wherein the second current has a current value substantially the same as the current value of the first current, wherein the current generator comprises: a current mirror unit which includes a current mirror and generates the first current and the second current; and a variable resistor which has a resistance value controlled by the current level controller and controls the current value of the first current, and wherein the current level controller controls the resistance value of the variable resistor in response to the duty ratio information of the pulse width modulation signal, and the resistance value of the variable resistor is substantially inversely proportional to the duty ratio of the pulse width modulation signal.