Abstract: A power tracking device for a power generation apparatus is provided. A multiplier generates a power level signal according to a current signal and a voltage signal both sensed from the output of the power generation apparatus. A sample-and-hold circuit samples the power level signal according to a sampling clock and generates a current level signal, a peak level signal, and a threshold level signal according to an update signal. A compare circuit compares the current, peak and threshold level signals to generate the update signal and a change signal. A converter performs pulse width modulation (PWM) to generate a PWM signal according to a control signal corresponding to the change signal and converts the output of the power generation apparatus to a load according to the PWM signal.