Driving circuit for light emitting diode

A driving circuit for a plurality of channels of light-emitting diodes providing a function as a backlight for a liquid crystal panel, comprising:

• an interface unit which receives, from an external processor, a luminance setting signal which specifies a luminance for each channel;
• a logic unit which receives a signal from the interface unit, and generates pulse signals, each having a duty ratio that corresponds to a luminance of the light emitting diode in the corresponding channel;
• a current setting unit which generates a constant current based upon an external voltage;
• a plurality of current mirror circuits, each of which generates based upon the constant current, a driving current to be applied to the light-emitting diode in corresponding channel;
• and
• a plurality of first transistors each of which switches the corresponding current mirror circuit between an ON state and an OFF state according to the pulse signal received from the logic unit, wherein the driving circuit is configured such that it can be switched between an independent driving mode in which the luminance of each of the plurality of channels of light-emitting diodes can be independently set according to an external signal and a parallel driving mode in which one selected from among the plurality of channels of light emitting diodes is driven by a plurality of the current mirror circuits.