M
TC64X/TC64XB FAN CONTROL
EVALUATION BOARD USER’S GUIDE
2003 Microchip Technology Inc. DS21403C-page 5
Chapter 2. Getting Started
This Chapter describes how the TC64X/TC64XB Fan Control Evaluation Board
functions and how to use the various features.
The development system demonstrates the ability of the TC64X and TC64XB families
to interface with virtually any brushless DC fan, control the speed of the fan according
to external temperature input, indicate overtemperature conditions, and detect fan
failure. A variety of test points and a user prototyping area are provided for easy and
complete design evaluation. The TC64X/TC64XB Evaluation Kit’s versatility and
ease-of-use helps speed up prototyping and development.
2.1 TC64X/TC64XB FAN CONTROL EVALUATION BOARD FUNCTIONAL
DESCRIPTION
2.1.1 Hardware Description
Various jumper options and sites for user-installed components allow the
TC64X/TC64XB Fan Control Evaluation Board to operate with virtually any BDC fan.
As shown in Figure A-1 of Appendix A. “Board Layout and Schematic”, the
TC64X/TC64XB Fan Control Evaluation Board operates with any of the TC64X and
TC64XB devices installed in the 8-pin DIP socket.
The TC646/646B/648/648B/649/649B devices have an auto-shutdown mode, whereby
the fan is shut off when measured temperature is below a prescribed minimum.
The TC642/2B/647/7B devices operate the fan continuously at a minimum speed when
the measured temperature is low. For details, please refer to the data sheets for these
devices. Shipped from the factory, the TC64X/TC64XB Fan Control Evaluation Board
is configured to operate as a TC642/2B/647/7B that drives a 12V BDC fan having a
100 mA maximum operating current.
The TC64X and TC64XB devices modulate fan speed in direct proportion to the control
signal applied to pin 1 (V
IN
). This input can be supplied by an off-board sensor, or from
the on-board speed control (Potentiometer 1), depending on the setting of the INT/EXT
switch. The minimum fan operating speed (TC642/2B/647/7B) or auto-shutdown
temperature setting (TC646/6B/648/8B/649/9B) is determined by the setting of
Potentiometer 2. Additionally, the TC64X and TC64XB devices can be manually shut
down (or reset) by pushing the SHDN/RESET switch or by applying a short between
the two terminals of TB
4
. Be sure JB
4
is set to match the TC64X and TC64XB devices
currently in service. The BDC fan modulation frequency should be between 15 Hz to
30 Hz. This frequency is determined either by capacitor C
1
,
or the user-installed
capacitor C
2
, and the setting of JB
1
. The default operating frequency is 30 Hz (see the
TC64X and TC64XB data sheets for details).
