Text version of the page

A1444 and A1445 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

Features and Benefits Description

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 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 sensor 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,

Package: Functional Block Diagram

6-contact MLP/DFN1.5 mm × 2 mm.0.40 mm maximum overall height(EW package) Approximate size Continued on the next page…

VDD Reverse Battery Output Full Bridge Q1Q3Q2Q4 SLEEP Power and SleepMode Control Active BrakingControl Drive LogicandSoft SwitchingControl GND VOUT1 Stall Detection 0.1 F VOUT2 AmHallElementp M Thermal ShutdownProtection PDC
ESD PWMControl

1444-DS