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參數(shù)資料
| 型號： | ML4425CS |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 運動控制電子 |
| 英文描述： | Sensorless BLDC Motor Controller |
| 中文描述： | BRUSHLESS DC MOTOR CONTROLLER, 0.05 A, PDSO28 |
| 封裝： | SOIC-28 |
| 文件頁數(shù)： | 9/16頁 |
| 文件大?。?/td> | 167K |
| 代理商： | ML4425CS |
PRODUCT SPECIFICATION
ML4425
REV. 1.0.2 7/2/01
9
The maximum frequency on the VCO pin is found by:
The voltage at the VCO/TACH pin is equal to the rotor
speed. The voltage at SPEED FB is controlled by the back
EMF sampler.
Back EMF Sampler
The input to the voltage controlled oscillator is the back
EMF sampler. The back EMF sense pins FB A, FB B, and
FB C inputs to the back EMF sampler require a signal from
the motor phase leads that is below the V
DD
of the ML4425.
The phase sense input impedance is 8k
. This requires a
series resistor RES1 from the motor phase lead as shown in
Figure 6 based on the following equation:
The back EMF sampler takes the motor phase voltages
divided down to signals that are less than V
DD
(12V nomi-
nal) and calculates the neutral point of the motor by the fol-
lowing equation:
This allows the ML4425 to compare the back EMF signal to
the motor’s neutral point without the need for bringing out an
extra wire on a WYE wound motor. For DELTA wound
motors there is no physical neutral to bring out, so this refer-
ence point must be calculated in any case.
Figure 5. External VCO Component Connections
The back EMF sampler measures the motor phase that is not
driven (i.e. if LA and HB are on, then phase A is driven low,
phase B is driven high, and phase C is sampled). The sam-
pled phase provides a back EMF signal that is compared
against the neutral of the motor. The sampler is controlled by
the commutation state machine. The sampled back EMF is
compared to the neutral through an error amplifier. The out-
put of the error amplifier outputs a charging or discharging
current to SPEED FB, which provides the control voltage to
the VCO.
f
MAX
0.05
N
×
RPM
MAX
×
=
(3)
RES1
670
V
V
MOTOR
10V
–
(
)
×
=
(4)
Neutral
------------+
+
=
(5)
CVCO
CVCO
4.3V
0V
5V
2.3V
RVCO
SPEED
FB
CVCO
RVCO
VOLTAGE
CONTROLLED
OSCILLATOR
VCO/TACH
VCO/TACH
RESET
(FROM CAT)
FROM
BACK EMF
SAMPLER
& RAMP
GENERATOR
Figure 6. Back EMF Sampler Detailed Block Diagram
NEUTRAL
SIMULATOR
Φ
A +
Φ
B +
Φ
C
6
MULTIPLEXER
COMMUTATION
STATE MACHINE
gm =
1
8k
4k
4k
4k
4k
4k
4k
+
–
SIGN
CHANGER
TO
SPEED FB
FB A
RES1
RES2
RES3
FB B
FB C
F/R
MOTOR
Φ
C
F/R
MOTOR
Φ
B
MOTOR
Φ
A
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相關代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ML4425CSX | 功能描述:開關變換器、穩(wěn)壓器與控制器 BLDC Motor Control Sensorless RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| ML4425IH | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Sensorless BLDC Motor Controller |
| ML4425IP | 功能描述:開關變換器、穩(wěn)壓器與控制器 BLDC Motor Control Sensorless RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| ML4425IS | 功能描述:開關變換器、穩(wěn)壓器與控制器 BLDC Motor Control Sensorless RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| ML4425ISX | 功能描述:開關變換器、穩(wěn)壓器與控制器 BLDC Motor Control Sensorless RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
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