Description
The A1444 and A1445 are full-bridge motor drivers designed to
drive low-voltage brushless DC (BLDC) motors in applications
that require rotor speed control and fast rotor start-stop cycles.
A high density CMOS semiconductor process allows the
integration of a Hall element, a full-bridge output driver, and
PWM speed control logic into one monolithic IC. Commutation
of the motor is achieved by use of a single Hall element
to detect the rotational position of an alternating-pole ring
magnet. Low-voltage design techniques have been employed
to achieve full device functionality down to a V
DD
of 1.8 V.
The voltage applied to the PDC pin is used to externally control
the maximum speed of the motor by adjusting the PWM duty
cycle of the output driver.
The A1444 and A1445 employ a soft switching algorithm to
reduce audible switching noise and EMI interference. The
externally controlled speed regulation and braking functions
can be used to create motor designs requiring faster start-stop
cycles. The A1444 and A1445 have different selectable internal
PWM duty cycle options to accommodate a wide range of
motor designs. Each device has a braking function enable
pin that also includes a micropower sleep mode for battery
management in portable electronic devices. This feature
eliminates the requirement for a FET transistor to switch the
device on and off.
The devices are optimized for vibration motor applications
that require fast start-stop cycles, such as in cellular phones,
1444-DS, Rev. 3
Features and Benefits
▪ Low voltage operation: 1.8 to 4.2 V
▪ Externally controlled motor speed regulation
▪ Fast motor startup and braking function allows faster
start-stop cycles
▪ Reverse voltage protection on the VDD and S
¯
¯
L
¯
¯
E
¯
¯
E
¯
¯
P
¯
pins
▪ Output short circuit and thermal shutdown protection
▪ Soft switching algorithm for reduced audible switching
noise and EMI interference
▪ Unidirectional operating mode results in motor rotation in
only one direction
▪ Chopper stabilization reduces Hall signal offset drifts and
results in increased signal accuracy over full operating
temperature range
▪ Sleep mode pin allows device enable/disable for reducing
average power consumption
▪ Antistall feature guarantees continuous rotation
▪ Single-chip solution for high reliability
▪ Miniature MLP/DFN package
Low-Voltage Full-Bridge Brushless DC Motor Driver
with Hall Commutation, Externally Controlled Speed Regulation, Soft Switching,
and Reverse Battery, Short Circuit, and Thermal Shutdown Protection
Continued on the next page…
Package:
Functional Block Diagram
A1444 and A1445
6-contact MLP/DFN
1.5 mm × 2 mm.
0.40 mm maximum overall height
(EW package)
Approximate size
Am
Hall
Element
p
Reverse Battery
Power and Sleep
Mode Control
Active Braking
Control
Stall Detection
Drive Logic
and
Soft Switching
Control
GND
VDD
VOUT1
Output
Full Bridge
Q1 Q3
Q2
Q4
SLEEP
VOUT2
Thermal Shutdown
Protection
M
0.1 μF
PDC
PWM Control
ESD
