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参数资料
| 型号： | FSCT17A-UH5 |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 运动控制电子 |
| 英文描述： | BRUSHLESS DC MOTOR CONTROLLER, PSIP5 |
| 封装： | IPPAK-5 |
| 文件页数： | 7/11页 |
| 文件大小： | 123K |
| 代理商： | FSCT17A-UH5 |
Obsolete
Product(s)
- Obsolete
Product(s)
FSCTxxA-UH5
5/11
DETAILED DESCRIPTION & APPLICATION INFORMATION
1. OUTPUT CHARACTERISTIC VERSUS TEMPERATURE
1.1 FAN speed control
As it's well known, BRUSHLESS DC motors present the advantage of a quasi-linear speed-voltage char-
acteristic. Hence, the fan speed is varying linearly versus the voltage which is applied across its terminals.
The FSCT Integrated Circuit provides at its OUT terminal, a voltage which changes versus the temperature
sensed through its tab. This OUT voltage decreases as temperature increases, following two modes of op-
eration. By connecting this OUT terminal to the Base of a PNP transistor, as shown in
figure 1, the FAN
voltage will increase with the sensed temperature.
The FAN voltage is given by the following equation:
VV
V
FAN
EB
OUT
=
+
(1)
Typically, for a 12 V VFAN+ anda1VVEB voltage, this gives:VV
FAN V
OUT V
()
=
11
(2)
It can be noticed that the PNP operates as a linear amplifier. This avoids EMI and acoustic noise compared
to Pulse Width Modulation control circuits.
1.2 ON/OFF Mode Selection
The
figure 6 gives the algorithm flowchart of the FSCT behavior. First, two modes of operation are distin-
guished by the ON pin signal.
s
Mode ON: activated when ON pin is at High Level or Not Connected (thanks to an internal Pull-up
curren source "IS")
s
Mode OFF: activated when ON pin is at Low Level.
During Mode ON, the OUT voltage follows a three-parts characteristic, according to its junction tempera-
ture (Tj):
s
Tj <TMS: in this case, VOUT is limited to VOMS to avoid stalling the fan rotor
s
TMS <Tj <TOL:VOUT is linearly regulated versus the junction temperature
s
Tj >TOL: in this case, VOUT is clamped to its minimum value (VOL).
During Mode OFF, an Hysteresis control allows
the system to switch to mode ON only if the tem-
perature exceeds the TON value. The Fan is turned
back off, if the system is cooled enough to lower
the temperature below TOFF.
The
figure 7 sums up the FSCT Output character-
istic versus the temperature, for the two operation
modes.
1.3 Minimum speed (mode ON)
Mode ON allows users to ensure that the FAN will
be always ON, whatever the ambient temperature
is.
The OUT voltage is clamped to VOMS for low tem-
perature (below TMS = 37 °C typically).
The VOMS has been set to 5.5 V max , thus the
minimum voltage applied across the FAN is 5.5 V
(according to
Equation 2). This voltage is above
stalling value of most fans and will then ensure that
the controlled FAN will always run, in mode ON,
avoiding spurious turn-off due to too low voltage at
low temperature. Annoying noises due to FAN
repetitive starts up are also suppressed.
yes
ON is
LOW
?
BEGIN
no
T
j >TON
?
yes
FAN OFF
V
OUT =VCC
FAN ON
V
OUT =VOMS –kSL.(Tj –TMS)
OR
V
OUT =VOL IF Tj >TOL
no
FAN ON
V
OUT =VOMS –kSL.(Tj –TMS)
OR
V
OUT =VOMS IF Tj <TMS
OR
V
OUT =VOL IF Tj >TOL
T
j <TOFF
?
no
yes
FAN OFF (V
OUT =VCC)
yes
ON is
LOW
?
BEGIN
no
T
j >TON
?
yes
FAN OFF
V
OUT =VCC
FAN ON
V
OUT =VOMS –kSL.(Tj –TMS)
OR
V
OUT =VOL IF Tj >TOL
no
FAN ON
V
OUT =VOMS –kSL.(Tj –TMS)
OR
V
OUT =VOMS IF Tj <TMS
OR
V
OUT =VOL IF Tj >TOL
T
j <TOFF
?
no
yes
FAN OFF (V
OUT =VCC)
Fig. 6: FSCT behavior flow-chart.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| FSCTEST | 制造商:Fairchild Semiconductor Corporation 功能描述:. |
| FSCTXXA-UH5 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:FAN SPEED CONTROLER |
| FSCUPMAD | 制造商:Intel 功能描述:Electrical Enclosure Accessories Air Duct Spare FSCUP MAD |
| FSCUPMAD 915622 | 制造商:Intel 功能描述:AIR DUCT SPARE - Bulk |
| FSCUPSAD | 制造商:Intel 功能描述:Electrical Enclosure Accessories Air Duct Spare FSCUP SAD |
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