ADT7468 Analog Devices, Inc., ADT7468 Datasheet - Page 48

• Manufacturer Part Number: ADT7468
• Description: Dbcool Remote Thermal Controller And Voltage Monitor
• Manufacturer: Analog Devices, Inc.

ADT7468
For a given T
at full speed for different PWM
calculated:
where:
T
T
Max DC is the maximum duty cycle (100%) = 255 decimal.
Min DC is equal to PWM
T
Example: Calculate T, given that T
and PWM
Example: Calculate T
and PWM
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.
MAX
MIN
RANGE
T
is the temperature at which the fan turns on.
T
T
T
T
T
T
T
T
T
is the temperature at which the fan runs full speed.
MAX
MAX
MAX
MAX
MAX
MAX
MAX
MAX
MAX
MAX
is the duty PWM duty cycle vs. temperature slope.
100%
50%
33%
25%
10%
Figure 64. Increasing PWM
= 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
= T
MIN
MIN
0%
RANGE
MIN
MIN
MIN
MIN
= 10% duty cycle = 26 (decimal).
= 25% duty cycle = 64 (decimal).
RANGE
+ (Max DC − Min DC) × T
+ (Max DC − Min DC) × T
+ (Max DC − Min DC) × T
+ T
value, the temperature at which the fan runs
RANGE
Function
T
MAX
MIN
, given that T
MIN
.
RANGE
RANGE
30°C
MIN
MIN
40°C
= 54°C)
= 45°C)
45°C
Changes Effective T
MIN
values can be easily
54°C
MIN
= 30°C, T
MIN
= 30°C, T
is equal to 33%
RANGE
RANGE
RANGE
RANGE
/170
/170
/170
RANGE
RANGE
= 40°C,
= 40°C,
Rev. A | Page 48 of 84
(1)
Example: Calculate T
and PWM
Example: Calculate T
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
Register 0x5F configures Remote 1 T
T
RANGE
T
T
T
T
T
T
T
T
. Register 0x61 configures Remote 2 T
RANGE
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
MIN
MIN
1
value can be selected for each temperature channel:
RANGE
MIN
MIN
= 33% duty cycle = 85 (decimal).
= 50% duty cycle = 128 (decimal).
+ (Max DC − Min DC) × T
+ (Max DC − Min DC) × T
Slope
MAX
MAX
T
2
2.5
3.33
4
5
6.67
8
10
13.33
16
20
26.67
32 (default)
40
53.33
80
RANGE
RANGE
, given that T
, given that T
RANGE
RANGE
Value
(°C)
RANGE
= 40°C)
= 30°C)
. Register 0x60 configures Local
RANGE
MIN
MIN
RANGE
.
= 30°C, T
= 30°C, T
value for each
RANGE
RANGE
/170
/170
RANGE
RANGE
= 40°C,
= 40°C,
RANGE
)