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参数资料
| 型号： | A3981KLPTR-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 21/43页 |
| 文件大小： | 0K |
| 描述： | IC MOTOR DVR MICROSTEP 28-TSSOP |
| 标准包装： | 1 |
| 系列： | * |
| 应用： | * |
| 输出数： | * |
| 电流 - 输出： | * |
| 电压 - 负载： | * |
| 电源电压： | * |
| 工作温度： | * |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SOIC（0.173"，4.40mm 宽）裸露焊盘 |
| 供应商设备封装： | 28-TSSOP 裸露焊盘 |
| 包装： | 标准包装 |
| 其它名称： | 620-1458-6 |
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A3981
Automotive, Programmable Stepper Driver
The magnitude of the resultant will be the square root of the sum
of the squares of these two currents:
and MS1 can be set to select full step, half step, quarter step, or
sixteenth step microstepping as follows:
| I 28 | ? I A 2 ? I B 2 ? 0 . 1406 ? 0 . 8499 ? 0 . 9953 (A)
So the resultant current magnitude is 99.53% of full scale. This
is within 0.5% of the target (100%) and is well within the ±5%
accuracy of the A3981.
The reference angle, zero degrees (0°), within the full electrical
MS1
0
0
1
1
MS0
0
1
0
1
Microstep Mode
Full step
Half step
Quarter step
Sixteenth step
cycle (360°), is defined as the angle where I B is at +100% and I A
is zero. Each full step is represented by 90° in the electrical cycle
so each one-sixteenth microstep is: 90°/16 steps = 5.625°. The
target angle of each microstep position with the electrical cycle
is determined by the product of the Step Angle Number and the
angle for a single microstep. So for the example of figure 7:
28 ( TARGET ) ? 28 ? 5 . 625 ? ? 157 . 5 ?
The actual angle is calculated using basic trigonometry as:
MS0 and MS1 can be accessed through the serial interface or
directly on pins 13 and 12 respectively. The values of MS0 and
MS1 are defined as the logical OR of the logic level on the input
pins and the value in Configuration Register 0. The bits in the
register default to 0 so if the serial interface is not used then MS0
and MS1 are defined by the input pins alone. If only the serial
interface is used to set the microstep resolution, then the MS0 and
MS1 logic input pins should be tied low to ensure that the register
? 180 ? tan ? 1 ? ? A 28 ? ?
28( ACTUAL )
? I ?
? I B 28 ?
? 180 ? ? ? 22 . 1 ? ? 157 . 9 ?
retains full control over all resolutions. Note that the microstep
select variables, MS0 and MS1, are only used with the STEP
input; they can be ignored if the motor is fully controlled through
the serial interface.
So the angle error is only 0.4°. Equivalent to about 0.1% error in
360° and well within the current accuracy of the A3981.
Note that each phase current in the A3981 is defined by a 6-bit
DAC. This means that the smallest resolution of the DAC is
100 / 64 = 1.56% of the full scale, so the A3981 cannot produce
a resultant motor current of exactly 100% at each microstep. Nor
can it produce an exact microstep angle. However, as can be seen
from the calculations above, the results for both are well within
the specified accuracy of the A3981 current control. The resultant
motor current angle and magnitude are also more than precise
enough for all but the highest precision stepper motors.
With the phase current table, control of a stepper motor is simply
a matter of increasing or decreasing the Step Angle Number
to move around the phase diagram of figure 7. This can be in
predefined multiples using the STEP input, or it can be variable
using the serial interface.
Using Step and Direction Control
The STEP input moves the motor at the microstep resolution
defined by the two microstep select variables, MS0 and MS1,
logic levels. The DIR input defines the motor direction. These
inputs define the output of a translator which determines the
required Step Angle Number in the phase current table. The MS0
In sixteenth step mode the translator simply increases or
decreases the Step Angle Number on each rising edge of the
STEP input, depending on the logic state of the DIR input. In the
other three microstep resolution modes the translator outputs spe-
cific Step Angle Numbers as defined in the phase current table.
Full step uses four of the entries in the phase current table. These
are 8, 24, 40, and 56 as shown in figure 8. Note that the four posi-
tions selected for full step are not the points at which only one
current is active, as would be the case in a simple on-off full step
driver. There are two advantages in using these positions rather
than the single full current positions. With both phases active, the
power dissipation is shared between two drivers. This slightly
improves the ability to dissipate the heat generated and reduces
the stress on each driver.
The second reason is that the holding torque is slightly improved
because the forces holding the motor are mainly rotational rather
than mainly radial.
Half step uses eight of the entries in the phase current table.
These are 0, 8, 16, 24, 32, 40, 48, and 56 as shown in figure 9.
Quarter step uses sixteen of the entries in the phase current table.
These are 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56,
and 60 as shown in figure 10.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
21
相关PDF资料 |
PDF描述 |
|---|---|
| A3982SLB-T | IC MOTOR DRIVER STEPPER 24-SOIC |
| A3983SLP-T | IC MICRO STEPPING DRIVER 24-TSSO |
| A3984SLP-T | IC MICRO STEPPING DRIVER 24-TSSO |
| A3986SLDTR-T | IC DRIVER MICROSTEPPING 38-TSSOP |
| A3987SLPTR-T | IC DRIVER MICROSTEPPING 24-TSSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| A3982 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:DMOS Stepper Motor Driver with Translator |
| A3982_13 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:DMOS Stepper Motor Driver with Translator |
| A3982SLB | 功能描述:IC MOTOR DRIVER STEPPER 24-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 电机和风扇控制器，驱动器 系列:- 标准包装:1 系列:- 应用:直流电机驱动器，步进电机驱动器 评估套件:- 输出数:1 或 2 电流 - 输出:750mA 电压 - 负载:10 V ~ 40 V 电源电压:4.5 V ~ 5.5 V 工作温度:-20°C ~ 70°C 安装类型:表面贴装 封装/外壳:24-BFSOP（0.295"，7.50mm 宽） 供应商设备封装:24-SOP 包装:Digi-Reel® 其它名称:MTS62C19A-HS105DKR |
| A3982SLB-T | 功能描述:IC MOTOR DRIVER STEPPER 24-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 电机和风扇控制器，驱动器 系列:- 标准包装:1 系列:- 应用:直流电机驱动器，步进电机驱动器 评估套件:- 输出数:1 或 2 电流 - 输出:750mA 电压 - 负载:10 V ~ 40 V 电源电压:4.5 V ~ 5.5 V 工作温度:-20°C ~ 70°C 安装类型:表面贴装 封装/外壳:24-BFSOP（0.295"，7.50mm 宽） 供应商设备封装:24-SOP 包装:Digi-Reel® 其它名称:MTS62C19A-HS105DKR |
| A3982SLB-T | 制造商:Allegro MicroSystems 功能描述:Motor Driver IC |
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