Motor tuning integrated with 12-V motor driver family

December 09, 2014 // By Graham Prophet
Adaptive current regulation and enhanced fault protection help systems spin stepper motors smoothly and reliably; TI has added a 12-V motor driver family that claims to reduces spin-up time to seconds and simplifies tuning stepper and brushed DC motors.

The DRV8846 incorporates a proprietary adaptive current control technology that automatically tunes motor performance for precise, smooth and quiet motion. The DRV8848 simplifies designs by using a simple pulse-width modulation (PWM) control interface and minimal external components. Both devices are fully protected against fault conditions. Target applications include 3D printers; IP security cameras; refrigerator damper control; heating, ventilation and air conditioning (HVAC); home automation equipment; and robotic vacuums.

DRV8846 and DRV8848 feature;

- Zero tuning effort: Adaptive current regulation, available on the DRV8846, dynamically changes current regulation schemes according to load conditions, with no configuration required. This simplifies system-level tuning and debugging, which allows end equipment manufactures to get their products to market more quickly.

- Smooth, quiet motion: The DRV8846's 1/32 micro-stepping indexer, coupled with adaptive current regulation, provides minimal current ripple, which enables smooth, precise motion profiles and reduced acoustic noise.

- High integration: The DRV8848 can operate without current sense resistors, leaving supply decoupling capacitors as the only external components required for operation. More precise motor operation can be achieved by including the resistors and enabling on-chip current regulation.

- Full fault protection: Advanced on-chip protection, including over-current protection, thermal shutdown, under-voltage lockout and diagnostics with fault condition feedback, protect both the motor driver and motor, reducing design complexity.

Two new fully-tested TI Designs reference designs are available; the 3D printer reference design is a complete three-axis, single-extruder system that uses the DRV8846’s adaptive current regulation to precisely drive four stepper motors from a single 12-V supply. A refrigerator damper and fan motor control design uses the DRV8848 integrated motor driver for airflow and direction control inside a refrigerator in a single-layer printed circuit board (PCB) design.

The DRV8846EVM and DRV8848EVM evaluation modules (EVMs) include a graphical user interface (GUI) via MSP430 microcontroller, and USB interfaces, for US$49.

For those wishing to learn more about brushed DC motor drive stage design, the BOOST-DRV8848 BoosterPack kit is available