ADT7473 Analog Devices, Inc., ADT7473 Datasheet - Page 38

• Manufacturer Part Number: ADT7473
• Description: Dbcool Remote Thermal Monitor And Fan Controller
• Manufacturer: Analog Devices, Inc.

ADT7473
STEP 3: T
CALIBRATION CHANNELS
T
automatic fan control. The speed at which the fan runs at T
programmed later. The T
channel specific, for example, 25°C for ambient channel, 30°C
for VRM temperature, and 40°C for processor temperature.
T
can be programmed in 1°C increments. A T
associated with each temperature measurement channel:
Remote 1 local and Remote 2 temperature. Once the T
is exceeded, the fan turns on and runs at the minimum PWM
duty cycle. The fan turns off once the temperature drops below
T
To overcome fan inertia, the fan is spun up until two valid
TACH rising edges are counted. (See the Fan Startup Timeout
section for more details.) In some cases, primarily for psycho-
acoustic reasons, it is desirable that the fan never switches off
below T
(0x62), when set, can keep the fans running at the PWM
minimum duty cycle, if the temperature falls below T
MIN
MIN
MIN
is the temperature at which the fans start to turn on und
is an 8-bit value, either twos complement or
− T
MIN
HYST
. Bits [7:5] of Enhance Acoustics Register 1
MIN
.
SETTINGS FOR THERMAL
MIN
values chosen are temperature
MIN
register is
Offset 64, that
MIN
MIN
.
value
MI
Rev. A | Page 38 of 76
N
er
is
T
Register 0x67, Remote 1 Temperature T
Register 0x68, Local Temperature T
Register 0x69, Remote 2 Temperature
Enhance Acoustics Register 1 (0x62)
Bit 7
temp
Bit 7 (MIN3) = 1, PWM3 runs at PWM3 minimum d
belo
Bit 6 (MIN2) = 0, PWM2 is o
temperature is below T
Bit 6
belo
Bit 5 (MIN1) = 0, PW
temperature is below T
Bit 5 (MIN1) =
below T
MIN
w T
w T
Registers
(MIN3) = 0, PWM3 is of
erature is below T
(MIN2) = 1, PWM2 runs at PWM2 minim
MIN
MIN
MIN
− T
− T
− T
HYST
HYST
HYST
1, PWM1 runs at PWM1 minimum duty cycle
.
.
.
M1 is off (0% PWM duty cycle) when
MIN
MIN
MIN
− T
− T
− T
ff (0% PWM
f (0% PWM duty cycle) when
HY
HYST
HYST
ST
.
.
.
MIN
T
= 0x9A (90°C)
MIN
MIN
duty cycle) when
= 0x9A (90°C
= 0x9A (90°C)
um duty cycle
uty cycle
)