Browse Prior Art Database

Fan Speed Control Based on Primary Current of a Power Supply

IP.com Disclosure Number: IPCOM000110702D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Patterson, BE: AUTHOR [+2]

Abstract

Disclosed is a circuit for controlling the speed of a fan, such as a cooling fan mounted in a power supply of a personal computer, in response to the measurement of current within the primary circuit of the power supply.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Fan Speed Control Based on Primary Current of a Power Supply

      Disclosed is a circuit for controlling the speed of a fan, such
as a cooling fan mounted in a power supply of a personal computer, in
response to the measurement of current within the primary circuit of
the power supply.

      Referring to the figure, primary current is provided as an
input to a transformer 10, the output of which is directed to a
detector circuit 12, which converts the current output of transformer
10 to a voltage provided as an input to compare circuit 14.  In
compare circuit 14, this voltage is compared to a reference level 16
developed elsewhere in the power supply secondary circuits.  When
this reference level 16 is exceeded by the input voltage to compare
circuit 14, a signal is provided to a fan speed control circuit 18,
which controls the speed of the fan (not shown), increasing the speed
from a low to a high level.

      In addition, a primary over-current circuit 20 may be provided
for using the voltage output of detector circuit 12 to turn off the
power supply when an unsafe level of current is flowing in its
primary circuit.

      Disclosed anonymously.