An over temperature compensation control circuit is coupled to a conversion unit. The over temperature compensation control circuit includes a detection circuit, a temperature control resistor, and a comparison unit. The detection circuit provides a current signal responsive to an input voltage according to a voltage signal responsive to the input voltage of the conversion unit. The temperature control resistor generates a temperature control voltage according to the current signal. The comparison unit compares the temperature control voltage with a reference voltage to generate a control signal. The control signal represents whether a temperature of the conversion unit reaches an over temperature protection point.