參數(shù)資料
型號： ADT7473ARQZ-1REEL7
廠商： ANALOG DEVICES INC
元件分類： 溫度/濕度傳感器
英文描述： DIGITAL TEMP SENSOR-SERIAL, 8BIT(s), 2.50Cel, RECTANGULAR, SURFACE MOUNT
封裝： ROHS COMPLIANT, MO-137AB, QSOP-16
文件頁數(shù)： 26/72頁
文件大小： 1494K
代理商： ADT7473ARQZ-1REEL7
ADT7473/ADT7473-1
Rev. C | Page 32 of 72
PROGRAMMING THE AUTOMATIC FAN SPEED CONTROL LOOP
To understand the automatic fan speed control loop, it is
strongly recommended to use the ADT7473/ADT7473-1
evaluation board and software while reading this section.
This section provides the system designer with an understand-
ing of the automatic fan control loop, and provides step-by-step
guidance on effectively evaluating and selecting critical system
parameters. To optimize the system characteristics, the designer
needs to consider the system configuration, including the
number of fans, where they are located, and what temperatures
are measured in the particular system.
The mechanical or thermal engineer who is tasked with the
system thermal characterization should also be involved at the
beginning of the process.
AUTOMATIC FAN CONTROL OVERVIEW
The ADT7473/ADT7473-1 can automatically control the speed
of fans based on the measured temperature. This is done
independently of CPU intervention once initial parameters are
set up.
The ADT7473/ADT7473-1 has a local temperature sensor and
two remote temperature channels that can be connected to a
CPU on-chip thermal diode (available on Intel Pentium class
CPUs and other CPUs). These three temperature channels can
be used as the basis for automatic fan speed control to drive
fans using PWM.
Automatic fan speed control reduces acoustic noise by optimiz-
ing fan speed according to accurately measured temperature.
Reducing fan speed can also decrease system current consump-
tion. The automatic fan speed control mode is very flexible due
to the number of programmable parameters, including TMIN
and TRANGE. The TMIN and TRANGE values for a temperature
channel and, therefore, for a given fan, are critical because they
define the thermal characteristics of the system. The thermal
validation of the system is one of the most important steps in
the design process, so these values should be selected carefully.
Figure 49 gives a top-level overview of the automatic fan control
circuitry on the ADT7473/ADT7473-1. From a systems-level
perspective, up to three system temperatures can be monitored
and used to control three PWM outputs. The three PWM
outputs can be used to control up to four fans. The ADT7473/
ADT7473-1 allows the speed of four fans to be monitored. Each
temperature channel has a thermal calibration block, allowing
the designer to individually configure the thermal characteristics
of each temperature channel. For example, a designer can
decide to run the CPU fan when CPU temperature increases
above 60°C, and a chassis fan when the local temperature
increases above 45°C. At this stage, the designer has not
assigned these thermal calibration settings to a particular fan
drive (PWM) channel. The right side of Figure 49 shows
controls that are fan-specific. The designer has individual
control over parameters such as minimum PWM duty cycle, fan
speed failure thresholds, and even ramp control of the PWM
outputs. Automatic fan control, then, ultimately allows graceful
fan speed changes that are less perceptible to the system user.
MUX
THERMAL CALIBRATION
0%
TMIN
TRANGE
THERMAL CALIBRATION
100%
0%
TMIN
TRANGE
THERMAL CALIBRATION
100%
0%
TMIN
TRANGE
REMOTE 1
TEMP
LOCAL
TEMP
REMOTE 2
TEMP
04
68
6-
04
6
TACHOMETER 1
MEASUREMENT
PWM
CONFIG
PWM
MIN
PWM1
RAMP
CONTROL
(ACOUSTIC
ENHANCEMENT)
PWM
GENERATOR
TACHOMETER 2
MEASUREMENT
PWM
CONFIG
PWM
MIN
PWM2
RAMP
CONTROL
(ACOUSTIC
ENHANCEMENT)
PWM
GENERATOR
TACHOMETER 3
AND 4
MEASUREMENT
PWM
CONFIG
PWM
MIN
PWM3
RAMP
CONTROL
(ACOUSTIC
ENHANCEMENT)
PWM
GENERATOR
100%
TACH1
TACH2
TACH3
Figure 49. Automatic Fan Control Block Diagram
相關PDF資料
PDF描述
ADT7473ARQZ-1REEL DIGITAL TEMP SENSOR-SERIAL, 8BIT(s), 2.50Cel, RECTANGULAR, SURFACE MOUNT
ADT7476ARQZ-REEL7 DIGITAL TEMP SENSOR-SERIAL, 10BIT(s), 2.50Cel, RECTANGULAR, SURFACE MOUNT
ADT7482ARMZ-RL DIGITAL TEMP SENSOR-SERIAL, 11BIT(s), 2.5Cel, SQUARE, SURFACE MOUNT
ADT7482ARMZ-U2 DIGITAL TEMP SENSOR-SERIAL, 11BIT(s), 2.5Cel, SQUARE, SURFACE MOUNT
ADT7485ARMZ-REEL DIGITAL TEMP SENSOR-SERIAL, 16BIT(s), 1Cel, SQUARE, SURFACE MOUNT
相關代理商/技術參數(shù)
參數(shù)描述
ADT7473ARQZ-1RL 功能描述:板上安裝溫度傳感器 FAN CNTRLR/INT MON RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor
ADT7473ARQZ-REEL 功能描述:板上安裝溫度傳感器 FAN CNTRLR/INT MON RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor
ADT7473ARQZ-REEL7 功能描述:IC REMOTE THERMAL CTRLR 16QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱管理 系列:dBCool® 標準包裝:1 系列:- 功能:溫度監(jiān)控系統(tǒng)（傳感器） 傳感器類型:內(nèi)部和外部 感應溫度:-40°C ~ 125°C，外部傳感器 精確度:±2.5°C 本地（最大值），±5°C 遠程（最大值） 拓撲:ADC，比較器，寄存器庫 輸出類型:2 線 SMBus? 輸出警報:無 輸出風扇:無 電源電壓:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-8 供應商設備封裝:SOT-23-8 包裝:Digi-Reel® 其它名稱:296-22675-6
ADT7473ARQZ-RL7 功能描述:板上安裝溫度傳感器 FAN CNTRLR/INT MON RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor
ADT7473EBZEVB 功能描述:EVALUATION BOARD ADT7473 制造商:on semiconductor 系列:* 零件狀態(tài):在售 標準包裝:1
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