Abstract: A temperature control apparatus for a pulse width modulation (PWM) device. The temperature control apparatus includes a temperature detector installed around the PWM device for detecting a present working temperature of the PWM device, and a temperature comparator coupled to the temperature detector and the PWM device for comparing the present working temperature with a maximum limiting temperature and a minimum limiting temperature. When the present working temperature is higher than the maximum limiting temperature, a working frequency of the PWM device will be reduced in a step variation frequency, and when the present working temperature is lower than the minimum limiting temperature, the working frequency of the PWM device will be increased in the step variation frequency.