ADT7463 Analog Devices, ADT7463 Datasheet - Page 13

• Manufacturer Part Number: ADT7463
• Description: Dbcool Thermal Management Controller And Voltage Monitor
• Manufacturer: Analog Devices

STEP 7: DETERMINING T
CHANNEL
T
the temperature measured has dropped back below T
before the fan turns off. The premise for temperature
hysteresis (T
“chatter,” or cycle on and off regularly, whenever tem-
perature is hovering at about the T
The T
time needed for the system to cool down or heat up as
the fan is turning on and off. Values of hysteresis are
programmable in the range 1°C to 15°C. Larger values of
T
viously described. The T
REV. 0
HYST
HYST
is the amount of extra cooling a fan provides after
prevent the fans from chattering on and off as pre-
HYST
value chosen will determine the amount of
HYST
AMBIENT TEMP
REMOTE 2 =
REMOTE 1 =
VRM TEMP
) is that without it, the fan would merely
CPU TEMP
100%
LOCAL =
0%
Figure 17. The T
T
HYST
HYST
HYST
T
MIN
T
T
FOR EACH TEMPERATURE
T
MIN
MIN
THERMAL CALIBRATION
THERMAL CALIBRATION
THERMAL CALIBRATION
default value is set at 4°C.
MIN
MIN
HYST
T
RANGE
setting.
T
T
T
RANGE
RANGE
RANGE
Value Applies to Fan On/Off Hysteresis and THERM Hysteresis
T
THERM
100%
100%
0%
100%
0%
0%
MUX
MIN
–13–
PWM
PWM
PWM
MIN
MIN
MIN
Note that the T
temperature hysteresis for fan turn on/off, but the same
setting is used for the T
in Step 6. So programming registers 0x6D and 0x6E sets
the hysteresis for both fan on/off and the THERM function.
HYSTERESIS REGISTERS
Reg. 0x6D Remote 1, Local Hysteresis Register
<7:4> = Remote 1 Temp Hysteresis (4°C default)
<3:0> = Local Temp Hysteresis (4°C default)
Reg. 0x6E Remote 2 Temp Hysteresis Register
<7:4> = Remote 2 Temp Hysteresis (4°C default)
Note that in some applications, it is required that the
fans not turn off below T
PWM
(Reg. 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
ENHANCEMENT)
TACHOMETER 1
MEASUREMENT
ENHANCEMENT)
TACHOMETER 2
MEASUREMENT
ENHANCEMENT)
TACHOMETER 3
MEASUREMENT
(ACOUSTIC
(ACOUSTIC
(ACOUSTIC
CONTROL
CONTROL
CONTROL
MIN
AND 4
RAMP
RAMP
RAMP
MIN
. Bits <7:5> of Enhance Acoustics Register 1
.
GENERATOR
GENERATOR
GENERATOR
CONFIG
CONFIG
CONFIG
PWM
PWM
PWM
PWM
PWM
PWM
HYST
MIN
. If the fans are always on, the T
setting applies not only to the
THERM
PWM1
TACH1
PWM2
TACH2
PWM3
TACH3
MIN
hysteresis value described
but remain running at
AN-613
CPU
FAN SINK
FRONT
CHASSIS
REAR
CHASSIS
HYST