Getting Started
2003 Microchip Technology Inc. DS21403C-page 7
2.2 IMPLEMENTING THE TC64X/TC64XB FAN CONTROL EVALUATION BOARD
Initial start-up of the TC64X/TC64XB Fan Control Evaluation Board is simplified by
using a 12V BDC fan with an operating current between 75 mA to 100 mA. The
TC64X/TC64XB Fan Control Evaluation Board is shipped pre-configured for such a
fan. If such a fan is available, please proceed to Step 1 below.
If such a fan is unavailable, the TC64X/TC64XB Fan Control Evaluation Board will
require modification to certain component values and jumper settings. Proceed to
Section 2.3, “Operation in the Adjustable Output Voltage”.
1. The TC64X/TC64XB Fan Control Evaluation Board is shipped from the factory
configured as outlined in Table 2-1. Inspect the jumper settings on the board to
ensure they match those listed in Table 2-1. Also be sure that a 4.7Ω resistor is
installed for R
3
, a 1.1 kΩ resistor is installed for R
2
, a 0.1 µF capacitor is installed
for C
5
and a 2N2222A transistor is installed for Q
2
.
2. Connect the positive side of a 5V DC supply to V
DD
(BP
1
) and the negative side
of the supply to GND (BP
2
).
3. Connect the positive lead of a 12V, 100 mA (max) BDC fan to the FAN + terminal.
Connect the negative lead of the fan to the FAN - terminal.
4. Connect the positive lead of a 12V DC supply to V
FAN
(BP
3
). Connect the
negative lead from the 12V DC supply to ground (BP
2
).
5. Set the INT/EXT switch to INT (Internal Control Voltage). Turn Potentiometer 1
(Speed Control) fully clockwise. Turn Potentiometer 2 (min speed/auto-shutdown
level) fully clockwise.
6. Turn both DC supplies on. The fan should immediately run to full speed and the
FAULT LED should be lit. If this is not the case, check the configuration settings
and repeat steps 1 through 5.
7. Connect the positive lead of a DC voltmeter to test point TP
1
and the negative
voltmeter lead to ground. This is the minimum speed setting voltage. Adjust
Potentiometer 2 until a reading of 1.9V is achieved. This voltage corresponds to
a minimum speed setting of approximately 40 percent of full speed.
8. Verify proper operation of the TC642/2B/647/7B by rotating Potentiometer 1
counterclockwise. The fan speed decreases and the FAULT LED goes off. Fan
speed will decrease as Potentiometer 1 is rotated counterclockwise until the
voltage on the wiper of Potentiometer 1 is less than the voltage on the wiper of
Potentiometer 2, at which time the fan will operate continuously at 40 percent of
full speed. Verify the minimum speed circuit is operating by adjusting
Potentiometer 2 clockwise, while Potentiometer 1 is fully counterclockwise.
9. Verify open fan detection by disconnecting one lead of the fan while it is running.
The FAULT LED will light after a disconnect time of about two seconds.
10. Verify locked rotor detection by stopping the fan blades during operation. The
FAULT LED will light approximately two seconds after the fan blades are
stopped.
The TC64X/TC64XB circuit board may now be custom-configured for your particular
combination of control and fan requirements.
