TC665TEUN View Datasheet(PDF) - Microchip Technology
Part Name
Description
Manufacturer
TC665TEUN Datasheet PDF : 36 Pages
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TC664/TC665
4.0 DEVICE OPERATION
The TC664/TC665 devices allow you to control, moni-
tor and communicate (via SMBus) fan speed for 2-wire
and 3-wire DC brushless fans. By pulse width modulat-
ing (PWM) the voltage across the fan, the TC664/
TC665 controls fan speed according to the system tem-
perature.The goal of temperature proportional fan
speed control is to reduce fan power consumption,
increase fan life and reduce system acoustic noise.
With the TC664/TC665 devices, fan speed can be con-
trolled by the analog input VIN or the SMBus interface,
allowing for high system flexibility.
The TC664/TC665 devices also measure and monitor
fan revolutions per minute (RPM). A fan’s speed (RPM)
is a measure of its health. As a fan’s bearings wear out,
the fan slows down and eventually stops (locked rotor).
By monitoring the fan’s RPM level, the TC664/TC665
devices can detect open, shorted, unconnected and
locked rotor fan conditions. The fan speed threshold
can be set to provide a predictive fan failure feature.
This feature can be used to give a system warning and,
in many cases, help to avoid a system thermal shut-
down condition. The fan RPM data and threshold reg-
isters are available over the SMBus interface which
allows for complete system control.
The TC664/TC665 devices are identical in every
aspect except for how they indicate an over-tempera-
ture condition. When VIN voltage exceeds 2.6 V (typi-
cal), both devices will set OTF (bit 5<X>) in the Status
Register to a '1'. The TC665 will additionally pull the
FAULT output low during an over-temperature
condition.
+5 V
+12 V
R1
34.8 k
R2
14.7 k
NTC Thermistor
100 k @ 25°C
1 VIN
C1
0.01 µF
2
CF
CF 1.0 µF
RSCLK +5 V
20 k
PIC®
+5 V
Microcontroller
RSDA
20 k
3
SCLK
4
SDA
10
VDD
TC664
TC665
GND
5
C2
1 µF
FAN
9
VOUT
RISO
715
8 CSENSE
SENSE
0.1 µF
7
NC
RSENSE
+5 V
6
FAULT
RFAULT
20 k
Note: Refer to Table 7-1 for RSENSE value.
FIGURE 4-1:
Typical Application Circuit.
2002-2013 Microchip Technology Inc.
DS21737B-page 9
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