A1448 ALLEGRO [Allegro MicroSystems], A1448 Datasheet - Page 4

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A1448

Manufacturer Part Number
A1448
Description
Low-Voltage, Full-Bridge Brushless DC Motor Driver with Integrated Hall Sensor IC, PWM Speed Control, Soft-Switching
Manufacturer
ALLEGRO [Allegro MicroSystems]
Datasheet
A1448
Soft Switching
The A1448 device includes a soft-switching algorithm that
controls the output switching slew rate for both output pins. As a
result, the A1448 device is ideal for use in applications requiring
low audible switching noise and low EMI. The resistance of the
output transistors is controlled to ensure the smooth switching of
the outputs, as illustrated in figure 1.
CONTROL Pin Functionality: PWM, Braking, and Sleep
Mode Input
The CONTROL input pin accepts an external signal that can
control the speed of the output bridge, initiate active braking,
and put the device into sleep mode. Signals higher than the V
Figure 1. A1448 output soft switching with a 30 Ω resistive load
Integrated Hall Sensor IC, PWM Speed Control, Soft-Switching,
V
V
Functional Description
Low-Voltage, Full-Bridge Brushless DC Motor Driver with
OUT2
OUT1
INHI
and Reverse Battery and Short Circuit Protection
t
SW
threshold will turn on the output bridge according to the applied
magnetic field. Applying a PWM signal to the CONTROL pin
will turn the bridge on and off according to the PWM duty cycle.
When the CONTROL pin is pulled to GND, the device initiates
its internal active braking algorithm to stop the motor. After
braking, the device enters micro-power sleep mode. The device
becomes active again when the CONTROL pin is pulled higher
than V
Antistall Algorithm
If a stall condition occurs, the device will execute an antistall
algorithm to re-start the motor.
INHI
.
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
4

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