參數(shù)資料
型號(hào)： TC646VUA
廠商： Microchip Technology Inc.
英文描述： PWM Fan Speed Controller with Auto-Shutdown and FanSense⑩ Technology
中文描述： PWM風(fēng)扇帶自動(dòng)調(diào)速器關(guān)斷和FanSense⑩技術(shù)
文件頁(yè)數(shù)： 13/28頁(yè)
文件大?。?/td> 473K
代理商： TC646VUA
2002 Microchip Technology Inc.
DS21446C-page 13
TC646
FIGURE 5-4:
SENSE Network.
FIGURE 5-5:
SENSE Waveforms.
Table 5-1 lists the recommended values of R
SENSE
based on the nominal operating current of the fan. Note
that the current draw specified by the fan manufacturer
may be a worst-case rating for near-stall conditions and
not the fan’s nominal operating current. The values in
Table 5-1 refer to actual average operating current. If
the fan current falls between two of the values listed,
use the higher resistor value. The end result of employ-
ing Table 5-1 is that the signal developed across the
sense resistor is approximately 450 mV in amplitude.
TABLE 5-1:
R
SENSE
VS. FAN CURRENT
5.5
Output Drive Transistor Selection
The TC646 is designed to drive an external transistor
or MOSFET for modulating power to the fan. This is
shown as Q
1
in Figures 5-1, 5-4, 5-6, 5-7, 5-8 and 5-9.
The V
OUT
pin has a minimum source current of 5 mA
and a minimum sink current of 1 mA. Bipolar transistors
or MOSFETs may be used as the power switching
element, as shown in Figure 5-7. When high current
gain is needed to drive larger fans, two transistors may
be used in a Darlington configuration. These circuit
topologies are shown in Figure 5-7: (a) shows a single
NPN transistor used as the switching element; (b)
illustrates the Darlington pair; and (c) shows an N-
channel MOSFET.
One major advantage of the TC646’s PWM control
scheme versus linear speed control is that the power
dissipation in the pass element is kept very low.
Generally, low cost devices in very small packages,
such as TO-92 or SOT, can be used effectively. For
fans with nominal operating currents of no more than
200 mA, a single transistor usually suffices. Above
200 mA, the Darlington or MOSFET solution is
recommended. For the fan sensing function to work
correctly, it is imperative that the pass transistor be fully
saturated when “on”.
Table 5-2 gives examples of some commonly available
transistors and MOSFETs. This table should be used
as a guide only since there are many transistors and
MOSFETs which will work just as well as those listed.
The critical issues when choosing a device to use as
Q
1
are: (1) the breakdown voltage (V
(BR)CEO
or V
DS
(MOSFET)) must be large enough to withstand the
highest voltage applied to the fan (
Note:
This will occur
when the fan is off); (2) 5 mA of base drive current must
be enough to saturate the transistor when conducting
the full fan current (transistor must have sufficient
gain); (3) the V
OUT
voltage must be high enough to suf-
ficiently drive the gate of the MOSFET to minimize the
R
DS(on)
of the device; (4) rated fan current draw must
be within the transistor's/MOSFET's current handling
capability; and (5) power dissipation must be kept
within the limits of the chosen device.
Q
1
GND
V
DD
R
SENSE
SENSE
R
BASE
C
SENSE
(0.1
μ
F Typ.)
V
OUT
Fan
1
Ch1 100mV
Tek Run: 10.0kS/s Sample
Ch2
100mV
M5.00ms Ch1
142mV
GND
[
T
]
T
Waveform @ Sense Resistor
90mV
50mV
GND
Waveform @ Sense Pin
2
Nominal Fan Current (mA)
R
SENSE
(
)
9.1
4.7
3.0
2.4
2.0
1.8
1.5
1.3
1.2
1.0
50
100
150
200
250
300
350
400
450
500
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TC646VUA713 功能描述:馬達(dá)/運(yùn)動(dòng)/點(diǎn)火控制器和驅(qū)動(dòng)器 Shtdn & Fault Dtct RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Stepper Motor Controllers / Drivers 類型:2 Phase Stepper Motor Driver 工作電源電壓:8 V to 45 V 電源電流:0.5 mA 工作溫度:- 25 C to + 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:HTSSOP-28 封裝:Tube
TC647 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:PWM Fan Speed Controller with FanSense Technology
TC647_13 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:PWM Fan Speed Controller with FanSensea?￠ Technology
TC647B 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSense⑩ Technology for Fault Detection
TC647BEOA 功能描述:馬達(dá)/運(yùn)動(dòng)/點(diǎn)火控制器和驅(qū)動(dòng)器 w/Rstrt & Flt Dtct RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Stepper Motor Controllers / Drivers 類型:2 Phase Stepper Motor Driver 工作電源電壓:8 V to 45 V 電源電流:0.5 mA 工作溫度:- 25 C to + 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:HTSSOP-28 封裝:Tube
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