Over voltage protection circuit and driver circuit using the same

A driver circuit, adapted for driving a light emitting unit having at least a light emitting diode, a first end of the light emitting unit being coupled to a power terminal, the driver circuit comprising:

• a chip, coupled to a second end of the light emitting unit, for driving the light emitting unit;
• and
• an over voltage protection circuit, coupled between the power terminal and a power pin of the chip, the over voltage protection circuit comprising:
• a voltage detection unit, coupled between the power terminal and a ground, for outputting a setting voltage according to a voltage level at the power terminal;
• a current limiting component, coupled between the power terminal and the power pin of the chip;
• and
• a switch component, coupled between the power pin of the chip and the ground, wherein the switch component is further coupled to the voltage detection unit and operates according to the setting voltage;
• wherein the switch component conducts to cut off voltage being received by the chip, when the voltage level at the power terminal is higher than a first predetermined value.