Patent ID: 8339052

Claim:
A power supply apparatus for an active matrix organic light emitting diode (AMOLED), the power supply apparatus comprising: a load checker which compares a load current of the AMOLED with a first reference voltage, and outputs a result of the comparison as a load check signal; and a frequency oscillator for generating a clock signal, which has a variable frequency, in response to the load check signal, wherein the frequency oscillator comprises: a current source which supplies a constant current; a plurality of capacitors electrically connected in parallel between the constant current and the ground; a first switch electrically connected between a part of the capacitors and the ground, the first switch being switched in response to the load check signal; a second switch electrically connected to a remaining part of the capacitors in parallel, the second switch being switched in response to the clock signal; and a switching unit for outputting the clock signal in accordance with a result of a comparison of voltages respectively charged in the capacitors with second reference voltages.