参数资料
型号: TC647BEPA
元件分类: 运动控制电子
英文描述: BRUSHLESS DC MOTOR CONTROLLER, PDIP8
封装: 0.300 INCH, PLASTIC, DIP-8
文件页数: 10/34页
文件大小: 683K
代理商: TC647BEPA
TC642B/TC647B
DS21756B-page 18
2003 Microchip Technology Inc.
Example: The following design goals are desired:
Duty Cycle = 50% (VIN = 1.90 V) with
Temperature (T1) = 30°C
Duty Cycle = 100% (VIN = 2.60 V) with
Temperature (T2) = 60°C
Using a 100 k
thermistor (25°C value), look up the
thermistor values at the desired temperatures:
RT (T1) = 79428 @ 30°C
RT (T2) = 22593 @ 60°C
Substituting these numbers into the given equations
produces the following numbers for R1 and R2.
R1 = 34.8 k
R2 = 14.7 k
FIGURE 5-2:
How Thermistor Resistance,
VIN, and RTEMP Vary With Temperature.
Figure 5-2 graphs RT, RTEMP (R1 in parallel with RT)
and VIN versus temperature for the example shown
above.
5.3
Thermistor Selection
As with any component, there are a number of sources
for thermistors. A listing of companies that manufacture
thermistors can be found at www.temperatures.com/
thermivendors.html. This website lists over forty
suppliers of thermistor products. A brief list is shown
here.
5.4
FanSense Network
(RSENSE and CSENSE)
The FanSense Network (comprised of RSENSE and
CSENSE) allows the TC642B and TC647B devices to
detect commutation of the fan motor. RSENSE converts
the fan current into a voltage. CSENSE AC couples this
voltage signal to the SENSE pin. The goal of the sense
network is to provide a voltage pulse to the SENSE pin
that has a minimum amplitude of 90 mV. This will
ensure that the current pulse caused by the fan
commutation is recognized by the TC642B/TC647B
device.
A 0.1 F ceramic capacitor is recommended for
CSENSE. Smaller values will require that larger sense
resistors be used. Using a 0.1 F capacitor results in
reasonable values for RSENSE. Figure 5-3 illustrates a
typical SENSE network.
FIGURE 5-3:
Typical Sense Network.
The required value of RSENSE will change with the cur-
rent rating of the fan and the fan current waveshape. A
key point is that the current rating of the fan specified
by the manufacturer may be a worst-case rating, with
the actual current drawn by the fan being lower. For the
purposes of setting the value for RSENSE, the operating
fan current should be measured to get the nominal
value. This can be done by using an oscilloscope cur-
rent probe or by using a voltage probe with a low value
resistor (0.5
). Another good tool for this exercise is
the TC642 Evaluation Board. This board allows the
RSENSE and CSENSE values to be easily changed while
allowing the voltage waveforms to be monitored to
ensure the proper levels are being reached.
Table 5-1 shows values of RSENSE according to the
nominal operating current of the fan. The fan currents
are average values. If the fan current falls between two
of the values listed, use the higher resistor value.
- Thermometrics
- Quality Thermistor
- Ametherm
- Sensor Scientific
- U.S. Sensors
- Vishay
- Advanced Thermal
Products
- muRata
0
20
40
60
80
100
120
140
20
30
40
50
60
70
80
90
100
Temperature (C)
Network
Resistance
(k
)
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
V
IN
(V)
NTC Thermistor
100 k @ 25C
VIN Voltage
RTEMP
FAN
RISO
RSENSE
CSENSE
SENSE
VOUT
(0.1 F typical)
715
Note: See Table 5-1 for RSENSE values.
相关PDF资料
PDF描述
TC54VC1601EZB 1-CHANNEL POWER SUPPLY SUPPORT CKT, PBCY3
TLVH431AQDBZR 1-OUTPUT THREE TERM VOLTAGE REFERENCE, 1.24 V, PDSO3
TPS62050DGSG4 1.4 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO10
TLVH431QDBZRG4 1-OUTPUT THREE TERM VOLTAGE REFERENCE, 1.24 V, PDSO3
TLVH431IBQDBZR 1-OUTPUT THREE TERM VOLTAGE REFERENCE, 1.24 V, PDSO3
相关代理商/技术参数
参数描述
TC647BEPA713 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSense⑩ Technology for Fault Detection
TC647BEPATR 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSense⑩ Technology for Fault Detection
TC647BEUA 功能描述:马达/运动/点火控制器和驱动器 w/Rstrt & Flt 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
TC647BEUA713 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSense⑩ Technology for Fault Detection
TC647BEUATR 功能描述:马达/运动/点火控制器和驱动器 w/Rstrt & Flt 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