A4962 Datasheet, PDF (1/42 Pages) Allegro MicroSystems – Sensorless BLDC Controller

A4962
Sensorless BLDC Controller
FEATURES AND BENEFITS
• Three phase sensorless BLDC motor control FET driver
• Logic level P-N gate drive (P high-side, N low-side)
• 4.2 V to 50 V supply range
• Simple block commutation for maximum torque
• Sensorless (bemf sensing) start-up and commutation
• Programmable operating modes:
□□Integrated Speed Control
□□PWM Duty Cycle Control
□□Current mode control
• Cross-conduction prevention
• Wide speed range capability
• Peak current limiting
• Single low frequency PWM control input
• Single Open Drain Fault output
• SPI compatible interface providing:
□□Configuration and control
□□Programmable dead time
□□Programmable phase advance
□□Detailed diagnostic reporting
APPLICATIONS
• Automotive Fuel, Oil, and Urea Pumps
• Automotive Fans and Blowers
PACKAGE:
20-Pin eTSSOP with Exposed Thermal Pad (suffix LP)
Not to scale
DESCRIPTION
The A4962 is a three-phase, sensorless, brushless DC (BLDC)
motor controller for use with external complementary P-channel
and N-channel power MOSFETs and is specifically designed
for automotive applications.
The A4962 can be used as a stand-alone controller
communicating directly with an electronic control unit (ECU)
or it can be used in a close coupled system with a local
microcontroller (MCU).
The motor is driven using block commutation (trapezoidal drive)
where phase commutation is determined, without the need for
independent position sensors, by monitoring the motor back-
EMF (bemf). The sensorless start-up scheme allows the A4962
to operate over a wide range of motor and load combinations.
Dedicated circuits allow theA4962 to operate over a wide range
of motor speeds, from less than 100 rpm to in excess of 30,000
rpm, depending on the supply voltage and motor capability.
Several operational modes are available including duty-cycle
(voltage) control, current (torque limit) control and closed loop
speed control. Operating mode and control parameters can be
altered through an SPI compatible serial interface.
Motor operation is controlled by a programmable PWM input
that can be used to define the motor operating state and provide
the proportional input for the selected operating mode.
Integrated diagnostics provide indication of under voltage,
over temperature and power bridge faults and can protect the
power switches under most short circuit conditions. Faults are
indicated by a single open drain output than can be used to
pull the PWM input low.
The A4962 is provided in a small, thermally enhanced 20-pin
TSSOP with exposed thermal pad.
ECU
COMMS
PWM
FAULTn
MCU
A4962
SPD
V
BAT
P
P
P
N
N
N
3-Phase
Motor
PWM
FAULTn
ECU
A4962
V
BAT
P
P
P
N
N
N
3-Phase
Motor
A4962-DS
Typical Application - Functional Block Diagrams