ADT7463 Analog Devices, ADT7463 Datasheet - Page 7

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

STEP 3: DETERMINING T
THERMAL CALIBRATION CHANNEL
T
turn on under automatic fan control. The speed at which
the fan runs at T
chosen will be temperature channel specific, e.g., 25°C
for ambient channel, 30°C for VRM temperature, and
40°C for processor temperature.
T
grammed in 1°C increments. There is a T
associated with each temperature measurement channel:
Remote 1, Local, and Remote 2 Temp. Once the T
value is exceeded, the fan turns on and runs at minimum
PWM duty cycle. The fan will turn off once temperature
has dropped 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 of the ADT7460/ADT7463 data sheet
for more details. In some cases, primarily for psycho-
acoustic reasons, it is desirable that the fan never
switches off below T
REV. 0
MIN
MIN
is an 8-bit twos complement value that can be pro-
is the temperature at which the fans will start to
AMBIENT TEMP
REMOTE 2 =
REMOTE 1 =
VRM TEMP
MIN
CPU TEMP
LOCAL =
is programmed later. The T
MIN
MIN
100%
. Bits <7:5> of enhance acoustics
0%
MIN
– T
HYST
T
T
T
SETTING FOR EACH
MIN
MIN
MIN
THERMAL CALIBRATION
THERMAL CALIBRATION
THERMAL CALIBRATION
T
(detailed later).
MIN
T
T
T
RANGE
RANGE
RANGE
Figure 7. Understanding the T
100%
100%
0%
100%
0%
0%
MIN
MIN
register
values
MUX
MIN
–7–
PWM
PWM
PWM
MIN
MIN
MIN
Register 1 (Reg. 0x62), when set, keeps the fans running
at PWM minimum duty cycle if the temperature should
fall below T
T
Reg. 0x67 Remote 1 Temp T
Reg. 0x68 Local Temp T
Reg. 0x69 Remote 2 Temp T
ENHANCE ACOUSTICS REG 1 (REG. 0x62)
Bit 7 (MIN3) = 0, PWM3 is OFF (0% PWM duty cycle)
when Temp is below T
Bit 7 (MIN3) = 1, PWM3 runs at PWM3 minimum duty
cycle below T
Bit 6 (MIN2) = 0, PWM2 is OFF (0% PWM duty cycle)
when Temp is below T
Bit 6 (MIN2) = 1, PWM2 runs at PWM2 minimum duty
cycle below T
Bit 5 (MIN1) = 0, PWM1 is OFF (0% PWM duty cycle)
when Temp is below T
Bit 5 (MIN1) = 1, PWM1 runs at PWM1 minimum duty
cycle below T
MIN
ENHANCEMENT
TACHOMETER 1
MEASUREMENT
ENHANCEMENT
TACHOMETER 2
MEASUREMENT
ENHANCEMENT
TACHOMETER 3
MEASUREMENT
MIN
(ACOUSTIC
(ACOUSTIC
(ACOUSTIC
CONTROL
CONTROL
CONTROL
REGISTERS
RAMP
RAMP
RAMP
AND 4
Parameter
MIN
MIN
MIN
MIN
GENERATOR
GENERATOR
GENERATOR
.
CONFIG
CONFIG
CONFIG
PWM
PWM
PWM
PWM
PWM
PWM
– T
– T
– T
HYST
HYST
HYST
MIN
MIN
MIN
MIN
.
.
.
PWM1
TACH1
PWM2
TACH2
PWM3
TACH3
– T
– T
– T
= 0x5A (90°C default)
MIN
MIN
HYST
HYST
HYST
= 0x5A (90°C default)
= 0x5A (90°C default)
.
.
.
AN-613
CPU
FAN SINK
FRONT
CHASSIS
REAR
CHASSIS