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參數(shù)資料
| 型號： | ML4428 |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | Sensorless Smart-Start BLDC PWM Motor Controller(無傳感智能啟動無刷直流PWM電機控制器) |
| 中文描述： | 智能傳感器啟動無刷電機控制器的PWM（無傳感智能啟動無刷直流脈寬調(diào)制電機控制器） |
| 文件頁數(shù)： | 6/16頁 |
| 文件大小： | 151K |
| 代理商： | ML4428 |
ML4428
6
REV. 1.0 11/17/2000
FUNCTIONAL DESCRIPTION
The ML4428 provides closed-loop commutation for
3-phase brushless motors. To accomplish this task, a VCO,
integrating back-EMF Sampling error amplifier and
sequencer form a phase-locked loop, locking the VCO to
the back-EMF of the motor. The IC contains circuitry to
control motor speed in PWM mode. Braking and power
fail detection functions are also provided on the chip. The
ML4428 is designed to drive external power transistors
(N-channel sinking transistors and P-channel sourcing
transistors) directly.
The ML4428 limits the motor current with a constant off-
time PWM controlled current. The velocity loop is
controlled with an on-board amplifier. An accurate, jitter-
free VCO output is provided equal to the commutation
frequency of the motor. The ML4428 switches the gates of
external N-channel power MOSFETs to regulate the motor
current and directly drives the P-channel MOSFETs for
12V motors. The ML4428 ensures that there is no shoot
through in any state of power drive to the FETs. Higher
voltage motors can be driven using buffer transistors or
standard “high side” drivers.
Speed sensing is accomplished by monitoring the output
of the VCO, which will be a signal which is phase-locked
to the commutation frequency of the motor.
BACK-EMF SENSING AND COMMUTATOR
The ML4428 contains a patented back-EMF sensing
circuit (Figure 1) which samples the phase which is not
energized (Shaded area in Figure 2) to determine whether
to increase or decrease the commutator (VCO) frequency.
A late commutation causes the error amplifier to charge
the filter (RC) on R
CVCO
, increasing the VCO input while
early commutation causes R
CVCO
to discharge. The
analog speed control loop uses R
CVCO
as a speed
feedback voltage.
The input impedance of the three PH inputs is about 8.7ky
to GND. When operating with a higher voltage motor, the
PH inputs should be divided down in voltage with series
resistors so that the maximum voltage at any PH input
does not exceed V
CC
.
NEUTRAL
0
60
120
180
240
0
300
Figure 2. Typical Motor Phase Waveform with back-EMF
Superimposed (Ideal Commutation).
Figure 1. Back-EMF Sensing Block Diagram
NEUTRAL
SIMULATOR
Φ
A +
Φ
B +
Φ
C
9
PHI1
PHI2
PHI3
MULTIPLEXER
R
C1
C2
VCO
COMMUTATION
LOGIC
SIGN
CHANGER
b
a
–
+
LOOP FILTER
I(RC) =
Va – Vb
4.35K
RC
VCO
2.9K
5.8K
VCO
22
23
24
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ML4428CP | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Sensorless Smart-Start⑩ BLDC PWM Motor Controller |
| ML4428CS | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Sensorless Smart-Start⑩ BLDC PWM Motor Controller |
| ML4428IP | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Sensorless Smart-Start⑩ BLDC PWM Motor Controller |
| ML4428IS | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Sensorless Smart-Start⑩ BLDC PWM Motor Controller |
| ML4428直流電機控制芯片 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述: |
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