參數(shù)資料
型號(hào)： AMD1027
廠商： Analog Devices, Inc.
英文描述： dBCOOL Remote Thermal Controller and Voltage Monitor
中文描述： dBCOOL遠(yuǎn)程熱控制器和電壓監(jiān)視器
文件頁(yè)數(shù)： 23/56頁(yè)
文件大?。?/td> 1072K
代理商： AMD1027
REV. A
ADM1027
–23–
FAN SPEED MEASUREMENTS
TACH Inputs
Pins 11, 12, 9, and 14 are open-drain TACH inputs intended
for fan speed measurement.
Signal conditioning in the ADM1027 accommodates the slow
rise and fall times typical of fan tachometer outputs. The maxi-
mum input signal range is 0 V to 5 V, even where V
CC
is less
than 5 V. In the event that these inputs are supplied from fan
outputs that exceed 0 V to 5 V, either resistive attenuation of
the fan signal or diode clamping must be included to keep
inputs within an acceptable range.
Figures 25a to 25d show circuits for most common fan TACH
outputs. If the fan TACH output has a resistive pull-up to V
CC
, it
can be connected directly to the fan input, as shown in Figure 25a.
5V OR 12V
ADM1027
FAN SPEED
COUNTER
TACH X
TACHO
OUTPUT
PULL-UP
4.7k
TYP
V
CC
FAN
Figure 25a. Fan With TACH Pull-Up to +V
CC
If the fan output has a resistive pull-up to 12 V (or other voltage
greater than 5 V), then the fan output can be clamped with a
Zener diode, as shown in Figure 25b. The Zener diode voltage
should be chosen so that it is greater than V
IH
of the TACH
input but less than 5 V, allowing for the voltage tolerance of the
Zener. A value of between 3 V and 5 V is suitable.
5V OR 12V
ADM1027
FAN SPEED
COUNTER
TACH X
TACHO
OUTPUT
PULL-UP
4.7k
TYP
V
CC
FAN
ZD1
*
*
CHOOSE ZD1 VOLTAGE APPROX 0.8 V
CC
Figure 25b. Fan with TACH Pull-Up to Voltage
> 5 V (e.g., 12 V) Clamped with Zener Diode
If the fan has a strong pull-up (less than 1 k ) to 12 V, or a
totem-pole output, then a series resistor can be added to limit
the Zener current, as shown in Figure 25c. Alternatively, a
resistive attenuator may be used, as shown in Figure 25d.
R1 and R2 should be chosen such that
2
The fan inputs have an input resistance of nominally 160 k
W
to
ground; this should be taken into account when calculating
resistor values.
2
1
2
5
V
V
R
R
R
R
V
PULLUP
PULLUP
<
￥
+
+
(
)
>
With a pull-up voltage of 12 V and pull-up resistor less than
1 k
W
, suitable values for R1 and R2 would be 100 k
W
and
47 k
W
. This will give a high input voltage of 3.83 V.
5V OR 12V
ADM1027
FAN SPEED
COUNTER
TACH X
TACHO
OUTPUT
PULL-UP TYP
<1k
OR
TOTEM POLE
V
CC
FAN
ZD1
*
*
CHOOSE ZD1 VOLTAGE APPROX 0.8 V
CC
R1
10k
Figure 25c. Fan with Strong TACH Pull-Up to > V
CC
or
Totem-Pole Output, Clamped with Zener and Resistor
5V OR 12V
ADM1027
FAN SPEED
COUNTER
TACH X
TACHO
OUTPUT
PULL-UP TYP
<1k
V
CC
FAN
R2
*
*
SEE TEXT
R1
*
Figure 25d. Fan with Strong TACH Pull-Up to > V
CC
or Totem-Pole Output, Attenuated with R1/R2
Fan Speed Measurement
The fan counter does not count the fan TACH output pulses
directly because the fan speed may be less than 1000 RPM and
it would take several seconds to accumulate a reasonably large
and accurate count. Instead, the period of the fan revolution is
measured by gating an on-chip 90 kHz oscillator into the input
of a 16-bit counter for N periods of the fan TACHO output
(Figure 26), so the accumulated count is actually proportional
to the fan tachometer period and inversely proportional to the
fan speed.
1
2
3
4
CLOCK
PWM
TACH
Figure 26. Fan Speed Measurement
N, the number of pulses counted, is determined by the settings
of Register 0x7B (fan pulses per revolution register). This register
contains two bits for each fan, allowing 1, 2 (default), 3, or 4
TACH pulses to be counted.
相關(guān)PDF資料
PDF描述
AME05 5 watt encapsulated ac-dc converter
AME05-12D 5 watt encapsulated ac-dc converter
AME05-12S 5 watt encapsulated ac-dc converter
AME05-15D 5 watt encapsulated ac-dc converter
AME05-15S 5 watt encapsulated ac-dc converter
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AMD-12V030W2AA 功能描述:30W 12V 2.5A 2PIN AC INNER 2.5MM RoHS:是 類別:電源 - 外部/內(nèi)部（非板載） >> AC DC 桌面、壁式變壓器 系列:AMD 標(biāo)準(zhǔn)包裝:40 系列:- 局部使用:適用于北美地區(qū) 形態(tài):壁式（2 管腳） 輸入電壓:120VAC 電壓 - 每連接器輸出:5V 電流 - 輸出（最大）:600mA 功率（瓦特）:3W 電源類型:線性（非穩(wěn)壓） 電極標(biāo)記:負(fù)極中心 纜線插頭:2.1mm 內(nèi)徑 x 5.5mm 外徑 x 9.5mm 母形 應(yīng)用:商用 特點(diǎn):- 效率:- 工作溫度:- AC 輸入連接器:- 線纜長(zhǎng)度:- 線路調(diào)節(jié):- 負(fù)載調(diào)整:- 重量:- 相關(guān)產(chǎn)品:CP-2225-ND - CORD YE-2013 GATOR CLIP SPT 1' 其它名稱:Q1710420
AMD-12V030W2BA 功能描述:30W 12V 2.5A 2PIN AC INNER 2.1MM RoHS:是 類別:電源 - 外部/內(nèi)部（非板載） >> AC DC 桌面、壁式變壓器 系列:AMD 標(biāo)準(zhǔn)包裝:40 系列:- 局部使用:適用于北美地區(qū) 形態(tài):壁式（2 管腳） 輸入電壓:120VAC 電壓 - 每連接器輸出:5V 電流 - 輸出（最大）:600mA 功率（瓦特）:3W 電源類型:線性（非穩(wěn)壓） 電極標(biāo)記:負(fù)極中心 纜線插頭:2.1mm 內(nèi)徑 x 5.5mm 外徑 x 9.5mm 母形 應(yīng)用:商用 特點(diǎn):- 效率:- 工作溫度:- AC 輸入連接器:- 線纜長(zhǎng)度:- 線路調(diào)節(jié):- 負(fù)載調(diào)整:- 重量:- 相關(guān)產(chǎn)品:CP-2225-ND - CORD YE-2013 GATOR CLIP SPT 1' 其它名稱:Q1710420
AMD-12V030W3AA 功能描述:30W 12V 2.5A 3PIN AC INNER 2.5MM RoHS:是 類別:電源 - 外部/內(nèi)部（非板載） >> AC DC 桌面、壁式變壓器 系列:AMD 標(biāo)準(zhǔn)包裝:40 系列:- 局部使用:適用于北美地區(qū) 形態(tài):壁式（2 管腳） 輸入電壓:120VAC 電壓 - 每連接器輸出:5V 電流 - 輸出（最大）:600mA 功率（瓦特）:3W 電源類型:線性（非穩(wěn)壓） 電極標(biāo)記:負(fù)極中心 纜線插頭:2.1mm 內(nèi)徑 x 5.5mm 外徑 x 9.5mm 母形 應(yīng)用:商用 特點(diǎn):- 效率:- 工作溫度:- AC 輸入連接器:- 線纜長(zhǎng)度:- 線路調(diào)節(jié):- 負(fù)載調(diào)整:- 重量:- 相關(guān)產(chǎn)品:CP-2225-ND - CORD YE-2013 GATOR CLIP SPT 1' 其它名稱:Q1710420
AMD-12V030W3BA 功能描述:30W 12V 2.5A 3PIN AC INNER 2.1MM RoHS:是 類別:電源 - 外部/內(nèi)部（非板載） >> AC DC 桌面、壁式變壓器 系列:AMD 標(biāo)準(zhǔn)包裝:40 系列:- 局部使用:適用于北美地區(qū) 形態(tài):壁式（2 管腳） 輸入電壓:120VAC 電壓 - 每連接器輸出:5V 電流 - 輸出（最大）:600mA 功率（瓦特）:3W 電源類型:線性（非穩(wěn)壓） 電極標(biāo)記:負(fù)極中心 纜線插頭:2.1mm 內(nèi)徑 x 5.5mm 外徑 x 9.5mm 母形 應(yīng)用:商用 特點(diǎn):- 效率:- 工作溫度:- AC 輸入連接器:- 線纜長(zhǎng)度:- 線路調(diào)節(jié):- 負(fù)載調(diào)整:- 重量:- 相關(guān)產(chǎn)品:CP-2225-ND - CORD YE-2013 GATOR CLIP SPT 1' 其它名稱:Q1710420
AMD150C-N02C-T 制造商:SMC Corporation of America 功能描述:MICRO MIST SEPARATOR, 1/4NPT, 2.2KW, NC DRAIN, SERVICE INDICATOR
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*