REV. A
32
ADM1027
Step 5
Determine T
RANGE
for Each Temperature Channel
T
RANGE
is the range of temperature over which automatic fan
control occurs once the programmed T
MIN
temperature has
been exceeded. T
RANGE
is actually a temperature slope and not
an arbitrary value, i.e., a T
RANGE
of 40rC only holds true for
PWM
MIN
= 33%. If PWM
MIN
is increased or decreased, the
effective T
RANGE
is changed, as described later.
TEMPERATURE
T
MIN
100%
PWM
MIN
0%
T
RANGE
Figure 32. T
RANGE
Parameter Affects Cooling Slope
The T
RANGE
or fan control slope is determined by the following
procedure:
1. Determine the maximum operating temperature for that
channel, e.g., 70rC.
2. Determine experimentally the fan speed (PWM duty cycle
value) will not exceed that temperature at the worst-case
operating points, e.g., 70rC is reached when the fans are
running at 50% PWM duty cycle.
3. Determine the slope of the required control loop to meet
these requirements.
4. Use best fit approximation to determine the most suitable
T
RANGE
value. There is ADM1027 evaluation software avail-
able to calculate the best fit value; ask your local Analog
Devices representative for more details.
T
MIN
100%
33%
0%
50%
30C
40C
Figure 33. Adjusting PWM
MIN
Affects T
RANGE
T
RANGE
is implemented as a slope, which means as PWM
MIN
is
changed, T
RANGE
changes, but the actual slope remains the
same. The higher the PWM
MIN
value, the smaller the effective
T
RANGE
will be, i.e., the fan will reach full speed (100%) at a
lower temperature.
T
MIN
100%
33%
0%
50%
30C
40C
25%
10%
45C
54C
Figure 34. Increasing PWM
MIN
Changes Effective T
RANGE
For a given T
RANGE
value, the temperature at which the fan
will run full-speed for different PWM
MIN
values can easily be
calculated:
T
T
MaxD.C. MinD.C. T
MAX
MIN
RANGE
=
+
-
(
)
?/DIV>
170
where:
T
MAX
= Temperature at which the fan runs full-speed
T
MIN
= Temperature at which the fan will turn on
MaxD.C. = Maximum duty cycle (100%) = 255 decimal
MinD.C. = PWM
MIN
T
RANGE
= PWM duty cycle versus temperature slope
Example: Calculate T
MAX
, given T
MIN
= 30rC, T
RANGE
= 40rC,
and PWM
MIN
= 10% duty cycle = 26 decimal
T
T
MaxD C
MinD C
T
MAX
MIN
RANGE
=
+
-
(
)
?/DIV>
. .
. .
170
T
C
C
MAX
= r +
-
(
)
?nbsp r
30
100
10
40
170
%
%
T
C
C
MAX
= r +
-
(
)
?nbsp r
30
255 26 40
170
T
MAX
= 84rC (effective T
RANGE
= 54rC)
Example: Calculate T
MAX
, given T
MIN
= 30rC, T
RANGE
= 40rC
and PWM
MIN
= 25% duty cycle = 64 decimal
T
T
MaxD C
MinD C
T
MAX
MIN
RANGE
=
+
-
(
)
?/DIV>
. .
. .
170
T
C
C
MAX
= r +
-
(
)
?nbsp r
30
100
25
40
170
%
%
T
C
C
MAX
= r +
-
(
)
?nbsp r
30
255 64 40
170
T
MAX
= 75rC (effective T
RANGE
= 45rC)
Rev. 3 | Page 32 of 56 | www.onsemi.com
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
ADM1029ARQZ-R7
IC SENSOR 2TEMP/FAN CTRL 24QSOP
ADM1030ARQZ-RL7
IC SNSR TEMP/FAN PWM CTRL 16QSOP
ADM1032ARZ-REEL
IC TEMP MONITOR 85DEG 8SOIC
ADM1033ARQZ-RL7
IC THERM/FAN SPEED CTLR 16-QSOP
ADM1034ARQZ-REEL
IC THERM/FAN SPEED CTRLR 16-QSOP
ADN8810ACPZ-REEL7
IC CURRENT SOURCE(12BIT) 24LFCSP
ADP2140ACPZ3328R7
IC REG DL BCK/LINEAR 10LFCSP
ADP5022ACBZ-6-R7
IC REG TRPL BCK/LINEAR 16WLCSP
相关代理商/技术参数
ADM1027ARQZ-RL71
制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:dBCOOLa?￠ Remote Thermal Controller and Voltage Monitor
ADM1028
制造商:AD 制造商全称:Analog Devices 功能描述:Remote Thermal Diode Monitor with Linear Fan Control
ADM1028ARQ
功能描述:IC SENSOR TEMP/FAN CTRL 16QSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 热管理 系列:- 标准包装:1 系列:- 功能:温度监控系统（传感器） 传感器类型:内部和外部 感应温度:-40°C ~ 125°C，外部传感器 精确度:±2.5°C 本地（最大值），±5°C 远程（最大值） 拓扑:ADC，比较器，寄存器库 输出类型:2 线 SMBus? 输出警报:无 输出风扇:无 电源电压:2.7 V ~ 5.5 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:SOT-23-8 供应商设备封装:SOT-23-8 包装:Digi-Reel® 其它名称:296-22675-6
ADM1028ARQ-REEL7
制造商:Rochester Electronics LLC 功能描述:TDM + LINEAR FAN CONTROL I.C. - Tape and Reel
ADM1029
制造商:AD 制造商全称:Analog Devices 功能描述:Dual PWM Fan Controller and Temperature Monitor for High Availability Systems
ADM1029ARQ
制造商:Rochester Electronics LLC 功能描述:TDM AND FAN CONTROLLER I.C. - Bulk
ADM1029ARQ-REEL7
制造商:Rochester Electronics LLC 功能描述: 制造商:Analog Devices 功能描述:
ADM1029ARQZ
功能描述:马达/运动/点火控制器和驱动器 +/- 1 C Digital Serial RoHS:否 制造商:STMicroelectronics 产品:Stepper Motor Controllers / Drivers 类型:2 Phase Stepper Motor Driver 工作电源电压:8 V to 45 V 电源电流:0.5 mA 工作温度:- 25 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:HTSSOP-28 封装:Tube