- 您现在的位置：买卖IC网 > PDF目录378256 > 8905 (Allegro MicroSystems, Inc.) 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING PDF资料下载
参数资料
| 型号： | 8905 |
| 厂商： | Allegro MicroSystems, Inc. |
| 英文描述： | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| 中文描述： | 3相无刷直流电动机控制器/驱动器，反电动势遥感 |
| 文件页数： | 7/12页 |
| 文件大小： | 163K |
| 代理商： | 8905 |
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
相关PDF资料 |
PDF描述 |
|---|---|
| 8906 | BIDIRECTIONAL 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING |
| 8909 | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING AND POWER DMOS OUTPUTS |
| 8910 | T-1 Subminiature Lamps |
| 8920 | DUAL SCHOTTKY DIODE |
| 8925 | 3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH LINEAR CURRENT CONTROL AND POWER DMOS OUTPUTS |
相关代理商/技术参数 |
参数描述 |
|---|---|
| 8905.2 | 功能描述:工业继电器 RMH1B High Current RelayModule, 5VDC, SPDT, 1Ch RoHS:否 制造商:TE Connectivity / Kilovac 触点形式:1 Form A (SPST-NO) 触点电流额定值: 线圈电压:9 VDC to 36 VDC 线圈电阻:38 Ohms 线圈电流: 切换电压: 安装风格:Panel 触点材料:Silver Palladium |
| 8905.3 | 功能描述:工业继电器 RMH4B, High Current RelayModule, 5VDC, SPDT, 4Ch RoHS:否 制造商:TE Connectivity / Kilovac 触点形式:1 Form A (SPST-NO) 触点电流额定值: 线圈电压:9 VDC to 36 VDC 线圈电阻:38 Ohms 线圈电流: 切换电压: 安装风格:Panel 触点材料:Silver Palladium |
| 89-050 | 制造商:Ideal Industries Inc 功能描述:RG6 BNC PLENM COMPR CONN |
| 8905-0.5" X 0.5"-1000 | 功能描述:3M 8905 POLYESTER TAPE - 0.5" X 制造商:3m (tc) 系列:8905 零件状态:在售 标准包装:1 |
| 8905-0.5" X 0.75"-1000 | 功能描述:3M 8905 POLYESTER TAPE - 0.5" X 制造商:3m (tc) 系列:8905 零件状态:在售 标准包装:1 |
发布紧急采购，3分钟左右您将得到回复。