- 您现在的位置：买卖IC网 > PDF目录16788 > APEK4986SLP-01-T (Allegro Microsystems Inc)Board Eval Motor Control A4986 PDF资料下载
参数资料
| 型号： | APEK4986SLP-01-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 6/17页 |
| 文件大小： | 0K |
| 描述： | Board Eval Motor Control A4986 |
| 标准包装： | 1 |
| 主要目的： | 电源管理，电机控制，步进控制器 |
| 嵌入式： | 否 |
| 已用 IC / 零件： | A4986 |
| 已供物品： | 板 |
| 相关产品： | 620-1342-2-ND - IC PWM MOTOR DRIVER 24TSSOP |
| 其它名称： | 620-1376 |
A4986
DMOS Dual Full-Bridge PWM Motor Driver
With Overcurrent Protection
Functional Description
Device Operation. The A4986 is designed to operate one
stepper motor in full, half, or quarter step mode. The currents in
each of the output full-bridges, all N-channel DMOS, are regu-
lated with fixed off-time pulse width modulated (PWM) control
circuitry. Each full-bridge peak current is set by the value of
an external current sense resistor, R S x , and a reference voltage,
V REF x .
Percentages of the peak current are set using a 2-bit nonlinear
DAC that programs 33%, 66%, or 100% of the peak current, or
disables the outputs.
Internal PWM Current Control. Each full-bridge is con-
trolled by a fixed off-time PWM current control circuit that limits
the load current to a desired value, I TRIP . Initially, a diagonal pair
of source and sink FET outputs are enabled and current flows
through the motor winding and the current sense resistor, R S x .
When the voltage across R S x equals the DAC output voltage, the
current sense comparator resets the PWM latch. The latch then
turns off the sink and source FETs.
The maximum value of current limiting is set by the selection of
R S x and the voltage at the VREF pin. The transconductance func-
tion is approximated by the maximum value of current limiting,
I TripMAX (A), which is set by
I TripMAX = V REF / ( 8 ? R S )
where R S is the resistance of the sense resistor ( Ω ) and V REF is
the input voltage on the REF pin (V).
The 2-bit DAC output reduces the V REF output to the current
sense comparator in precise steps, such that
ROSC terminal. The ROSC terminal has two settings:
? ROSC tied to VDD or ground — off-time internally set to
30 μ s
? ROSC through a resistor to ground — off-time is determined
by the following formula
t OFF ≈ R OSC ? 825
Where t OFF is in μ s.
Blanking. This function blanks the output of the current sense
comparators when the outputs are switched by the internal
current control circuitry. The comparator outputs are blanked
to prevent false overcurrent detection due to reverse recovery
currents of the clamp diodes, and switching transients related
to the capacitance of the load. The blank time, t BLANK ( μ s), is
approximately
t BLANK ≈ 1 μ s
Shorted-Load and Short-to-Ground Protection.
If the motor leads are shorted together, or if one of the leads is
shorted to ground, the driver will protect itself by sensing the
overcurrent event and disabling the driver that is shorted, protect-
ing the device from damage. In the case of a short-to-ground, the
device will remain disabled (latched) until the Sˉ ˉLˉ ˉEˉ ˉEˉ ˉP input goes
high or VDD power is removed. A short-to-ground overcurrent
event is shown in figure 1.
When the two outputs are shorted together, the current path is
through the sense resistor. After the blanking time ( ≈ 1 μ s) expires,
the sense resistor voltage is exceeding its trip value, due to the
overcurrent condition that exists. This causes the driver to go into
a fixed off-time cycle. After the fixed off-time expires the driver
turns on again and the process repeats. In this condition the driver
is completely protected against overcurrent events, but the short
is repetitive with a period equal to the fixed off-time of the driver.
This condition is shown in figure 2.
I trip = (%I TripMAX / 100)
× I TripMAX
If the driver is operating in Mixed decay mode, it is normal for
the positive current to spike, due to the bridge going in the for-
It is critical that the maximum rating (0.5 V) on the SENSE1 and
SENSE2 pins is not exceeded.
Fixed Off-Time. The internal PWM current control circuitry
uses a one-shot circuit to control the duration of time that the
DMOS FETs remain off. The off-time, t OFF , is determined by the
ward direction and also in the negative direction, as a result of the
direction change implemented by the Mixed decay feature. This
is shown in figure 3. In both instances the overcurrent circuitry is
protecting the driver and prevents damage to the device.
Charge Pump (CP1 and CP2). The charge pump is used to
generate a gate supply greater than that of VBB for driving the
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
6
相关PDF资料 |
PDF描述 |
|---|---|
| A3AAB-1036G | IDC CABLE- ASC10B/AE10G/ASC10B |
| EMC10DRTN | CONN EDGECARD 20POS .100 EXTEND |
| V24C28C100BG | CONVERTER MOD DC/DC 28V 100W |
| B78108S1102K9 | CHOKE RF 1.0UH 1.2A AXIAL |
| APEK4985SLP-01-T | Board Eval Motor Control A4985 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| APEK4986SLP-01-T-DK | 功能描述:A4986 - Power Management, Motor Control, Stepper Evaluation Board 制造商:allegro microsystems, llc 系列:- 零件状态:有效 主要用途:电源管理，电机控制，步进控制器 嵌入式:否 使用的 IC/零件:A4986 主要属性:- 辅助属性:- 所含物品:板 标准包装:1 |
| APEK4987SLP-01-T | 功能描述:BOARD EVAL MOTOR CONTROL A4987 RoHS:是 类别:编程器，开发系统 >> 评估演示板和套件 系列:- 标准包装:1 系列:PSoC® 主要目的:电源管理，热管理 嵌入式:- 已用 IC / 零件:- 主要属性:- 次要属性:- 已供物品:板，CD，电源 |
| APEK4987SLP-01-T-DK | 功能描述:A4987 - Power Management, Motor Control, Stepper Evaluation Board 制造商:allegro microsystems, llc 系列:- 零件状态:有效 主要用途:电源管理，电机控制，步进控制器 嵌入式:否 使用的 IC/零件:A4987 主要属性:- 辅助属性:- 所含物品:板 标准包装:1 |
| APEK4988SET-01-T-DK | 功能描述:A4988 - Power Management, Motor Control, Stepper Evaluation Board 制造商:allegro microsystems, llc 系列:- 零件状态:有效 主要用途:电源管理，电机控制，步进控制器 嵌入式:- 使用的 IC/零件:A4988 主要属性:- 辅助属性:- 所含物品:板 标准包装:1 |
| APEK4989SLD-01-T | 制造商:Allegro MicroSystems LLC 功能描述: |
发布紧急采购，3分钟左右您将得到回复。