Device for controlling current of LED

A device for controlling current of a light emitting diode (LED), the device comprising:

• a constant current generator;
• a current mirror;
• a current amplifier;
• a selector outputting an L signal or an H signal according to an input control signal;
• and
• a current changing unit including at least two switching units connected in parallel, each of the switching units including a transistor and a switch connected to the transistor in series,
• wherein the switch of each of the switching units in the current changing unit is controlled by the signal output from the selector, and
• wherein the selector has inverting terminals receiving the control signal, non-inverting terminals receiving voltages divided by at least one resistor, and at least one amplifier comparing a voltage of one of the inverting terminals with that of a corresponding one of the non-inverting terminals to output the L signal or the H signal to an output terminal.

A device for controlling current of an LED, comprising:

• a constant current generator;
• a current mirror including a first MOS transistor and a second MOS transistor;
• a selector outputting an L signal or an H signal according to an input signal;
• a MOS transistor having a source receiving driving power and a gate connected to a gate of the first MOS transistor;
• a current changing unit including a switch of which one end is connected to a drain of the MOS transistor;
• and
• a current amplifier having an input end connected to the other end of the switch of the current changing unit,
• wherein the switch is controlled by the signal output from the selector.