- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄375161 > A8905CLB (Allegro MicroSystems, Inc.) 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING PDF資料下載
參數(shù)資料
| 型號： | A8905CLB |
| 廠商： | Allegro MicroSystems, Inc. |
| 英文描述： | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| 中文描述： | 3相無刷直流電動機控制器/驅(qū)動器，反電動勢遙感 |
| 文件頁數(shù)： | 7/12頁 |
| 文件大小： | 163K |
| 代理商： | A8905CLB |
8905
3-PHASE BRUSHLESS DC
MOTOR CONTROLLER/DRIVER
Adaptive Commutation Delay.
The
adaptive commutation delay circuit uses the
back-EMF zero-crossing indicator signal
(FCOM) to determine an optimal commutation
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.
Dwg. WP-016-2
FCOM
t FCOM
t CD1
VCWD
VCD1
VCD2
t CD2
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 commutations occur approximately halfway
between zero crossings. The actual delay is
slightly less than halfway to compensate for
electrical delays in the motor, which improves
efficiency.
Because the commutation-delay capacitors
are adaptive in nature, the absolute value and
tolerance is not critical. In choosing these
capacitors, the voltage excursion should be 1.5 V to 2.5 V at rated speed.
Solving for C in the equation I = Cdv/dt, where dv = 2.5 V, I = 22
μ
A, and
20/RPM
#motor poles
dt = t
FCOM
=
Use of a capacitor slightly greater than this value will ensure that the commuta-
tion delay capacitors never charge to the high rail.
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.
t
BLANK
Dwg. WP-022
BLANK
CWD
V
V
TL
I
CD(charge),
[
I
CD(discharge)
]
WATCHDOG-TRIGGERED COMMUTATION
t
BLANK
t
WD
V
TL
V
TH
Dwg. WP-021
BLANK
CWD
V
NORMAL COMMUTATION
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| A8906CLB | BIDIRECTIONAL 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| A8909CLB | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING AND POWER DMOS OUTPUTS |
| A8920 | Dual Schottky Barrier Diodes(用于硬盤驅(qū)動器的20V反向電壓雙肖特基勢壘二極管) |
| A8920SLR | DUAL SCHOTTKY DIODE |
| A8932 | Voice-Coil Motor Driver(音頻線圈電機驅(qū)動器) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| A8906CLB | 制造商:ALLEGRO 制造商全稱:Allegro MicroSystems 功能描述:BIDIRECTIONAL 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| A8909CLB | 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 AND POWER DMOS OUTPUTS |
| A891 | 制造商:Thomas & Betts 功能描述:FIXTURE FITTING |
| A89120-000 | 制造商:TE Connectivity 功能描述:VARISTOR 82V 7MM STRAIGHT LEAD 制造商:TE Connectivity 功能描述:VARISTOR 82V 1.75KA DISC 7MM 制造商:TE CONNECTIVITY RAYCHEM-POLYSWITCH 功能描述:Var MOV 50VAC 65VDC 1750A 82V Thru-Hole Bulk |
| A89125-000 | 制造商:TE Connectivity 功能描述:VARISTOR 390VDC 7MM 10% LEADED 制造商:TE Connectivity 功能描述:VARISTOR 390V 1.2KA DISC 7MM |
發(fā)布緊急采購，3分鐘左右您將得到回復。