ADT7467 Analog Devices, Inc., ADT7467 Datasheet - Page 45

• Manufacturer Part Number: ADT7467
• Description: Dbcool Remote Thermal Monitor And Fan Controller
• Manufacturer: Analog Devices, Inc.

T
is changed, T
same. The higher the PWM
T
temperature.
For a given T
at full speed, which varies with the PWM
calculated:
where:
T
T
Max DC is the maximum duty cycle (100%) = 255 decimal.
Min DC is equal to PWM
T
Example 1: Calculate T, given that T
and PWM
Example 2: Calculate T
40°C, and PWM
RANGE
RANGE
MAX
MIN
RANGE
T
T
T
T
T
T
T
T
T
is the temperature at which the fan turns on.
is the temperature at which the fan runs full speed.
, that is, the fan reaches full speed (100%) at a lower
MAX
MAX
MAX
MAX
MAX
MAX
MAX
MAX
MAX
is the duty PWM duty cycle vs. temperature slope.
is implemented as a slope, which means that as PWM
100%
Figure 63. Increasing PWM
50%
33%
25%
10%
= T
= T
= 30°C + (100% − 10%) × 40°C/170
= 30°C + (255 − 26) × 40°C/170
= 84°C (Effective T
= T
= 30°C + (100% − 25%) × 40°C/170
= 30°C + (255 − 64) × 40°C/170
= 75°C (Effective T
MIN
0%
RANGE
RANGE
MIN
MIN
MIN
= 10% duty cycle = 26 (decimal).
MIN
+ (Max DC − Min DC) × T
+ (Max DC − Min DC) × T
+ (Max DC − Min DC) × T
value, the temperature at which the fan runs
changes, but the actual slope remains the
= 25% duty cycle = 64 (decimal).
T
MIN
MAX
MIN
, given that T
MIN
.
RANGE
RANGE
30°C
value, the smaller the effective
MIN
40°C
45°C
= 54°C)
= 45°C)
Changes Effective T
MIN
54°C
MIN
= 30°C, T
MIN
= 30°C, T
RANGE
RANGE
RANGE
value, can be easily
/170
RANGE
/170
/170
RANGE
RANGE
= 40°C,
=
MIN
Rev. A| Page 45 of 80
Example 3: Calculate T
40°C, and PWM
Example 4: Calculate T
40°C, and PWM
Selecting a T
The T
Remote 1, local, and Remote 2 temperature. Bits <7:4> (T
of Registers 0x5F to 0x61 define the T
temperature channel.
Table 15. Selecting a T
Bits <7:4>
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
1
Summary of T
When using the automatic fan control function, the
temperature at which the fan reaches full speed can be
calculated by
Equation 1 holds true only when PWM
PWM duty cycle.
Register 0x5F configures Remote 1 T
Register 0x60 configures local T
Register 0x61 configures Remote 2 T
T
T
T
T
T
T
T
T
T
RANGE
MAX
MAX
MAX
MAX
MAX
MAX
MAX
MAX
MAX
= T
= 30°C + (100% − 33%) × 40°C/170
= 30°C + (255 − 85) × 40°C/170
= 70°C (Effective T
= T
= 30°C + (100% − 50%) × 40°C/170
= 30°C + (255 − 128) × 40°C/170
= 60°C (Effective T
= T
1
value can be selected for each temperature channel:
MIN
MIN
MIN
RANGE
RANGE
MIN
MIN
+ (Max DC − Min DC) × T
+ (Max DC − Min DC) × T
+ T
Slope
= 33% duty cycle = 85 (decimal).
= 50% duty cycle = 128 (decimal).
RANGE
Function
T
2
2.5
3.33
4
5
6.67
8
10
13.33
16
20
26.67
32 (default)
40
53.33
80
MAX
MAX
RANGE
RANGE
, given that T
, given that T
RANGE
RANGE
RANGE
Value
(°C)
.
RANGE
RANGE
= 40°C)
= 30°C)
.
.
RANGE
MIN
MIN
MIN
= 30°C, T
= 30°C, T
is equal to 33%
value for each
RANGE
RANGE
/170
/170
ADT7467
RANGE
RANGE
RANGE
=
=
(1)
)