06040668 is referenced by 49 patents and cites 8 patents.

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.

Title
Monolithic fan controller
Application Number
8/749864
Publication Number
6040668
Application Date
November 14, 1996
Publication Date
March 21, 2000
Inventor
Donald E Alfano
Round Rock
TX, US
Joseph James Judkins III
Cedar Park
TX, US
Sang T Ngo
Cupertino
CA, US
Quoi V Huynh
San Jose
CA, US
Agent
Thomas E Law Offices of Thomas E Schatzel A Prof Corporation Schatzel
Assignee
TelCom Semiconductor
CA, US
IPC
G05B 5/00
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