ADT7476 Analog Devices, Inc., ADT7476 Datasheet - Page 46

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

ADT7476
STEP 6: T
T
control occurs once the programmed T
been exceeded. T
PWM
Otherwise stated, it is the line drawn between the T
and the (T
The T
1.
2.
3.
4.
As PWM
RANGE
Figure 58. Adjusting PWM
Determine the maximum operating temperature for the
channel (for example, 70°C).
Determine experimentally the fan speed (PWM duty cycle
value) that does not exceed the temperature at the worst-
case operating points. For example, 70°C is reached when
the fans are running at 50% PWM duty cycle.
Determine the slope of the required control loop to meet
these requirements.
Using the ADT7476 evaluation software, graphically
program and visualize this functionality. Ask your local
Analog Devices, Inc. representative for details.
MIN
RANGE
is the range of temperature over which automatic fan
PWM
MIN
100%
and 100% PWM where the fan speed changes linearly.
50%
33%
MIN
100%
0%
RANGE
is determined by the following procedure:
Figure 57. T
MIN
0%
is changed, the automatic fan control slope changes.
+ T
RANGE
FOR TEMPERATURE CHANNELS
RANGE
T
RANGE
MIN
)/PWM 100% intersection points.
is the temperature range between
T
MIN
MIN
Parameter Affects Cooling Slope
Changes the Automatic Fan Control Slope
30°C
T
RANGE
TEMPERATURE
MIN
temperature has
MIN
/PWM
Rev. B | Page 46 of 72
MIN
As T
the fans reach 100% speed with a smaller temperature change.
Selecting T
The T
Remote 1, local, and Remote 2 temperature. Bits [7:4] (T
of Register 0x5F to Register 0x61 define the T
each temperature channel.
RANGE
RANGE
Figure 60. Changing PWM
100%
100%
PWM
10%
is changed, the slope changes. As T
MAX
10%
0%
Figure 59. Increasing T
0%
value can be selected for each temperature channel:
RANGE
T
T
MIN–HYST
MIN–HYST
T
MIN
MAX
RANGE
T
30°C
RANGE
Does Not Change the AFC Slope
40°C
45°C
Changes the AFC slope
54°C
RANGE
RANGE
gets smaller,
value for
RANGE
)