ADT7467 Analog Devices, Inc., ADT7467 Datasheet - Page 50

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

ADT7467
STEP 9: OPERATING POINTS FOR
TEMPERATURE CHANNELS
The operating point for each temperature channel is the optimal
temperature for that thermal zone. The hotter each zone is
allowed to be, the more quiet the system, because the fans are
not required to run as fast. The ADT7467 increases or decreases
fan speeds as necessary to maintain the operating point
temperature, allowing for system-to-system variations and
eliminating the need to design for the worst case. If a sensible
operating point value is chosen, any T
in the system characterization. If the T
fans run sooner than required and the temperature is below the
operating point. In response, the ADT7467 increases T
keep the fans off longer and to allow the temperature zone to
approach the operating point. Likewise, too high a T
AMBIENT TEMP
REMOTE 2 =
REMOTE 1 =
VRM TEMP
CPU TEMP
LOCAL =
THERMAL CALIBRATION
THERMAL CALIBRATION
THERMAL CALIBRATION
T
T
T
MIN
MIN
MIN
Figure 69. Operating Point Value Dynamically Adjusts Automatic Fan Control Settings
MIN
MIN
value can be selected
value is too low, the
T
T
T
RANGE
RANGE
RANGE
100%
100%
100%
0%
0%
0%
MIN
MIN
value
MUX
to
Rev. A | Page 50 of 80
OPERATING
POINT
PWM
PWM
PWM
MIN
MIN
MIN
causes the operating point to be exceeded, and, in turn, the
ADT7467 reduces T
system.
Programming Operating Point Registers
There are three operating point registers, one for each
temperature channel. These 8-bit registers allow the operating
point temperatures to be programmed with 1°C resolution.
Operating Point Registers
Reg. 0x33, Remote 1 operating point = 0xA4 (100°C default)
Reg. 0x34, local operating point = 0xA4 (100°C default)
Reg. 0x35, Remote 2 operating point = 0xA4 (100°C default)
ENHANCEMENT)
ENHANCEMENT)
ENHANCEMENT)
TACHOMETER 1
MEASUREMENT
TACHOMETER 2
MEASUREMENT
TACHOMETER 3
MEASUREMENT
(ACOUSTIC
(ACOUSTIC
(ACOUSTIC
CONTROL
CONTROL
CONTROL
RAMP
RAMP
RAMP
AND 4
MIN
GENERATOR
GENERATOR
GENERATOR
CONFIG
CONFIG
CONFIG
PWM
PWM
PWM
PWM
PWM
PWM
to turn the fans on sooner to cool the
PWM1
TACH1
PWM2
TACH2
PWM3
TACH3
FRONT CHASSIS
REAR CHASSIS
CPU FAN SINK