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参数资料
| 型号： | TC649VOART |
| 元件分类： | 运动控制电子 |
| 英文描述： | BRUSHLESS DC MOTOR CONTROLLER, PDSO8 |
| 封装： | SOIC-8 |
| 文件页数： | 2/17页 |
| 文件大小： | 119K |
| 代理商： | TC649VOART |
10
TC649-2 12/05/00
TC649
PWM Fan Speed Controller with Auto-Shutdown
2001 Microchip Technology Inc.
DS21449A
SENSE Network (RSENSE and CSENSE)
The network comprised of RSENSE and CSENSE allows
the TC649 to detect commutation of the fan motor. This
network can be thought of as a differentiator and threshold
detector. The function of RSENSE is to convert the fan current
into a voltage. CSENSE serves to AC-couple this voltage
signal and provide a ground-referenced input to the SENSE
pin. Designing a proper SENSE Network is simply a matter
of scaling RSENSE to provide the necessary amount of gain,
i.e., the current-to-voltage conversion ratio. A 0.1
F ceramic
capacitor is recommended for CSENSE. Smaller values re-
quire larger sense resistors, and higher value capacitors are
bulkier and more expensive. Using a 0.1
F results in rea-
sonable values for RSENSE. Figure 6 illustrates a typical
SENSE Network. Figure 7 shows the waveforms observed
using a typical SENSE Network.
Table 1 lists the recommended values of RSENSE ac-
cording to the nominal operating current of the fan. Note that
the current draw specified by the fan manufacturer may not
be the fan’s nominal operating current, but may be a worst-
case rating for near-stall conditions. The values in the table
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 employing Table 1 is that the signal
developed across the sense resistor is approximately
450mV in amplitude.
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
Table 1. RSENSE vs. Fan Current
Nominal Fan Current (mA)
RSENSE (
)
50
9.1
100
4.7
150
3.0
200
2.4
250
2.0
300
1.8
350
1.5
400
1.3
450
1.2
500
1.0
Output Drive Transistor Selection
The TC649 is designed to drive an external transistor for
modulating power to the fan. This is shown as “Q1” in
Figures 1, 5, 6, 8, 9, and 11. The VOUT pin has a minimum
source current of 5mA and a minimum sink current of 1mA.
Bipolar transistors or MOSFETs may be used as the power
switching element as shown below. 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 8: (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 TC649’s PWM control
scheme versus linear speed control is that the 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 200mA, a single transistor usually suffices.
Above 200mA, the Darlington or MOSFET solution is rec-
ommended. For the fan sensing function to work correctly,
it is imperative that the pass transistor be fully saturated
when “on”. The minimum gain (hFE) of the transistor in
question must be adequate to fully saturate the transistor
when passing the full fan current and being driven within the
5mA IOH of the VOUT output.
Table 2 gives examples of some commonly available
transistors. This table is a guide only. There are many
transistor types which might work equally as well as those
listed. The only critical issues when choosing a device to use
as Q1 are: (1) the breakdown voltage, VCE(BR), must be large
enough to stand off the highest voltage applied to the fan
(NOTE: this may be when the fan is off!); (2) the gain (hFE)
must be high enough for the device to remain fully saturated
while conducting the maximum expected fan current and
being driven with no more than 5mA of base/gate drive at
maximum temperature; (3) rated fan current draw must be
within the transistor’s current handling capability; and (4)
Figure 7. SENSE Waveforms
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| TC649VUATR | BRUSHLESS DC MOTOR CONTROLLER, PDSO8 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TC649VOATR | 功能描述:马达/运动/点火控制器和驱动器 Shtdn & Fault Dtct 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 |
| TC649VPA | 功能描述:马达/运动/点火控制器和驱动器 Shtdn & Fault Dtct 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 |
| TC649VUA | 功能描述:马达/运动/点火控制器和驱动器 Shtdn & Fault Dtct 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 |
| TC649VUATR | 功能描述:马达/运动/点火控制器和驱动器 Shtdn & Fault Dtct 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 |
| TC6-4A11 | 制造商:FERROXCUBE 制造商全称:Ferroxcube International Holding B.V. 功能描述:Ferrite toroids |
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