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參數(shù)資料
| 型號(hào)： | A8902 |
| 廠商： | Allegro MicroSystems, Inc. |
| 英文描述： | Three-Phase Brushless DC Motor Controller/ Driver(用于5V或12V硬盤驅(qū)動(dòng)器的三相無刷直流電機(jī)控制器/驅(qū)動(dòng)器) |
| 中文描述： | 三相無刷直流電動(dòng)機(jī)控制器/驅(qū)動(dòng)器（用于5V的或12V的硬盤驅(qū)動(dòng)器的三相無刷直流電機(jī)控制器/驅(qū)動(dòng)器） |
| 文件頁數(shù)： | 7/12頁 |
| 文件大小： | 156K |
| 代理商： | A8902 |
8902–A
3-PHASE BRUSHLESS DC
MOTOR CONTROLLER/DRIVER
Blanking and Watchdog Timing Functions.
The blanking and
watchdog timing functions are derived from one timing capacitor, C
WD
.
V
TL
x C
WD
I
CWD
V
TH
x C
WD
I
CWD
where
t
BLANK
=
and
t
WD
=
The CWD capacitor begins charging at each commutation, initiating
the BLANK signal. BLANK is an internal signal that inhibits the back-
EMF comparators during the commutation transients, preventing errors
due to inductive recovery and voltage settling transients.
The watchdog timing function allows time to detect correct motor
position by checking the back-EMF polarity after each commutation. If
the correct polarity is not observed between t
BLANK
and t
WD
, then the
watchdog timer commutates the outputs to the next state to synchro-
nize the motor. This function is useful in preventing excessive reverse
rotation, and helps in resynchronizing (or starting) with a moving
spindle.
Adaptive Commutation Delay.
The
adaptive commutation delay circuit uses the
back-EMF zero-crossing indicator signal
(FCOM) to determine an optimal commuta-
tion time for efficient synchronous operation.
This circuit commutates the outputs, delayed
from the last zero crossing, using two
external timing capacitors, C
D1
and C
D2
,
to measure the time between crossings.
where t
CD
= t
FCOM
x
C
D1
charges up with a fixed current from
its 2.5 V reference while FCOM is high.
When FCOM goes low at the next zero
crossing, C
D1
is discharged at approximately
twice the charging current. When CD
1
reaches the CD threshold, a commutation
occurs. C
D2
operates similarly except on the
opposite phase of FCOM . Thus the com-
mutations occur approximately halfway
between zero crossings. The actual delay is
slightly less than halfway to compensate for
electrical delays in the motor, which im-
proves efficiency.
Dwg. WP-016-2
FCOM
t FCOM
t CD1
VCWD
VCD1
VCD2
t CD2
WATCHDOG-TRIGGERED
COMMUTATION
t
BLANK
Dwg. WP-022
BLANK
CWD
V
V
TL
NORMAL COMMUTATION
t
BLANK
t
WD
V
TL
V
TH
Dwg. WP-021
BLANK
CWD
V
I
CD(charge)
I
CD(discharge)
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| A8904SLB | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| A8904SLB-T | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| A8904SLP | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| A8904SLP-T | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| A8904 | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| A8902CLBA | 制造商:Allegro MicroSystems LLC 功能描述:DC Motor Driver 24-Pin SOIC(300mil) |
| A8902CLBAJ | 制造商:Allegro MicroSystems LLC 功能描述:2CLBAJ |
| A8902SLB | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:DC Motor Controller/Driver |
| A8903SLB | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:DC Motor Controller/Driver |
| A8904 | 制造商:ALLEGRO 制造商全稱:Allegro MicroSystems 功能描述:3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
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