12V to 24V, 27A Brushed DC Motor Reference Design

Brushed motors are a relatively popular motor design option due to their low price and simple control scheme. A brushed motor has a wound rotor and a permanent magnet stator. The motor is commutated via a conductive ring: this ring is connected to the rotor, which uses a brush to scrape against the commutator ring, thus commutation is achieved. Therefore, the direction of current flowing through the motor can change depending on the brush direction and different commutation rings. Simple direction changes and speed control changes can be quickly and efficiently implemented on brushed DC motors using an H-bridge. An electronic driver is required to control the motor current in a brushed DC motor. The electronic drive circuit contains a power stage with a two-phase inverter (to meet the required power intensity), a microcontroller for implementing motor speed commands and fault handling, a current sensing function for motor start/stop protection, for control Gate drivers for two-phase inverters and power supplies for microcontrollers and other low-voltage devices.

characteristic

• ● 343 Watt RMS power stage with MSP430G2553 control scheme
• ● Tested to be powered by 18V external battery
• ● Provides up to 27.47 ARMS continuous motor current without external cooling or airflow assistance
• ● 76.3mm x 38.1mm double-layer, small size PCB outline
• ● Utilizes TI's 60V N-channel NexFET with 1.8 mΩ RDS in SON 5mm × 6mm package
• ● User-configurable gate drive current helps easily adapt to custom MOSFET selections