ADT7476 Analog Devices, Inc., ADT7476 Datasheet - Page 50

• Manufacturer Part Number: ADT7476
• Description: Dbcool Remote Thermal Controller And Voltage Monitor
• Manufacturer: Analog Devices, Inc.

ADT7476
STEP 8: T
T
temperature measured has dropped back below T
fan turns off. The premise for temperature hysteresis (T
that, without it, the fan would merely chatter, or cycle on and
off regularly, whenever the temperature is hovering at about the
T
The T
for the system to cool down or heat up as the fan turns on and
off. Values of hysteresis are programmable in the range 1°C to
15°C. Larger values of T
and off. The T
The T
for fan on/off but also to the T
in Step 7. Therefore, programming Register 0x6D and Register
0x6E sets the hysteresis for both fan on/off and the THERM
function.
HYST
MIN
setting.
is the amount of extra cooling a fan provides after the
HYST
HYST
value chosen determines the amount of time needed
setting applies not only to the temperature hysteresis
HYST
HYST
FOR TEMPERATURE CHANNELS
default value is set at 4°C.
AMBIENT TEMP
REMOTE 2 =
REMOTE 1 =
VRM TEMP
CPU TEMP
LOCAL =
HYST
100%
0%
prevent the fans from chattering on
THERM
THERMAL CALIBRATION
THERMAL CALIBRATION
THERMAL CALIBRATION
T
T
T
T
MIN
Figure 65. The T
MIN
MIN
MIN
hysteresis value, described
T
RANGE
T
T
T
RANGE
RANGE
RANGE
HYST
MIN
T
100%
100%
100%
THERM
0%
0%
0%
Value Applies to Fan On/Off Hysteresis and THERM Hysteresis
before the
HYST
MUX
) is
Rev. B | Page 50 of 72
PWM
PWM
PWM
MIN
MIN
MIN
CONFIG
CONFIG
CONFIG
In some applications, it is required that fans not turn off below
T
Acoustics Register 1 (0x62) allow the fans to be turned off or to
be kept spinning below T
value has no effect on the fan when the temperature drops
below T
THERM Hysteresis
Any hysteresis programmed via Register 0x6D and Register 0x6E
also applies to hysteresis on the appropriate THERM channel.
TACHOMETER 1
MEASUREMENT
TACHOMETER 2
MEASUREMENT
TACHOMETER 3
MEASUREMENT
MIN
PWM
PWM
PWM
GENERATOR
GENERATOR
GENERATOR
AND 4
but remain running at PWM
PWM
PWM
PWM
MIN
.
ENHANCEMENT)
ENHANCEMENT)
ENHANCEMENT)
(ACOUSTIC
(ACOUSTIC
(ACOUSTIC
CONTROL
CONTROL
CONTROL
RAMP
RAMP
RAMP
MIN
. If the fans are always on, the T
PWM1
TACH1
PWM2
TACH2
PWM3
TACH3
MIN
. Bits [7:5] of Enhanced
FRONT CHASSIS
REAR CHASSIS
CPU FAN SINK
HYST