Abstract: Disclosed herein is a monolithic fan controller circuit which provides the following features: a special start-up routine for the fan; a fan fault detector; a thermal fault detector; an automatic speed controller; a minimum speed controller; a routine for attempting to clear temporary fan faults; and a controllable drive signal frequency. A start-up control circuit provides an initial high duty-cycle kick to the fan in order to initiate the rotation of the fan. A temperature sensor, which may be external or internal to the monolithic fan controller, supplies a signal which is proportional to measured temperature. This signal is used to control the output pulse width of a pulse-width modulator (PWM) or control the frequency of a pulse frequency modulator (PFM). The PWM or PFM output signal regulates the speed of the brushless (or brush) DC fan motor. In a preferred embodiment, the monolithic fan controller has 8 pins.