Patent ID: 6650074
Filing Date: 2003-11-18
Classification: G06F,H02P,H05K,Y02D

Abstract:
An information handling system, comprising:a microprocessor for executing instructions stored in a memory coupled thereto; a fan for cooling said microprocessor during operation thereof, said fan comprising a fan motor and a fan blade coupled to a shaft of said fan motor, wherein the shaft rotation speed is proportionate to a direct current (DC) voltage level applied to said fan motor, and said fan motor has a tachometer output for indicating the shaft rotation speed; a voltage regulator coupled between said fan motor and a first DC power source, said voltage regulator controlling the DC voltage level applied to said fan motor, wherein the DC voltage level applied to said fan motor can be any voltage from about ground to about the first DC power source voltage; a power management controller having a speed control pulse output and a tachometer pulse input; a pulse-to-DC voltage converter, said pulse-to-DC voltage converter coupled between the speed control pulse output of said power management controller and a control input of said voltage regulator; and a tachometer pulse amplifier coupled between the tachometer output of said fan motor and the tachometer pulse input of said power management controller, whereby said power management controller controls said fan motor shaft speed.