Patent ID: 6617815
Filing Date: 2003-09-09
Classification: G06F,H05K,Y10S

Abstract:
A motor control circuit for a computer system fan motor, comprising a temperature measuring circuit for outputting a signal representative of the voltage to be applied across fan motor terminals, and a feedback control arrangement for applying a voltage across fan motor terminals according to said signal,wherein the feedback control arrangement comprises subtraction circuitry, fan control circuitry, and a feedback loop, said subtraction circuitry receiving the signal outputted by said temperature sensing circuit and a signal outputted by said feedback loop, and outputting to the fan control circuitry a signal representative of a difference between the signal outputted by said temperature sensing circuit and the signal outputted by said feedback loop, said fan control subtraction circuit applying across said fan motor terminals a voltage representative of the signal supplied by the subtraction circuitry, said feedback loop outputting to said subtraction circuitry a signal representative of the voltage applied to the fan motor terminals.