Brushless Motor Control PC Board

18V/400W high-efficiency (98%), non-inductive, with locked-rotor current limiting function, compact for brushless DC motor drives in power tools

Description

18A RMS driver for three-phase brushless DC (BLDC) motors in power tools powered by 5 lithium-ion batteries (maximum voltage 21V). This design is a compact 45 x 50 mm driver that enables sensor-based trapezoidal control. The design uses a discrete compact MOSFET-based three-phase inverter that provides 18A RMS continuous (60A peak for 1 second) winding current without the need for any external cooling devices or heat sinks. The slew rate control of the gate driver and charge pump ensures maximum inverter efficiency (>98%, 18V DC) and best EMI performance. The cycle-by-cycle overcurrent protection function prevents large stall currents in the power stage, and the board can operate at ambient temperatures up to 55°C. The small form factor supports flexible board placement, high efficiency makes the battery last longer, and the 60A peak current capacity can provide high instantaneous peak torque in power tools.

Characteristic
  • Operating voltage range is 15V to 21V (5 lithium-ion batteries) and has RMS continuous (60A peak for 1 second) winding current up to 18A, no heat sink or airflow required
  • PCB is compact: 45mm x 50mm
  • Optimal inverter efficiency (>97%, 10.8V) and EMI performance are achieved by using low RDS_ON NexFET and slew rate control of gate driver and charge pump function
  • Cycle-by-cycle overcurrent protection, response time is less than 1us, short circuit latch protection breakdown protection, under-voltage protection, overtemperature protection, and rotor stall protection are provided through VDS sensing
Technical Parameter
  • Operating voltage range is 15V to 21V (5 lithium-ion batteries) and has RMS continuous (60A peak for 1 second) winding current up to 18A, no heat sink or airflow required
  • PCB is compact: 45mm x 50mm
  • Optimal inverter efficiency (>97%, 10.8V) and EMI performance are achieved by using low RDS_ON NexFET and slew rate control of gate driver and charge pump function
  • Cycle-by-cycle overcurrent protection, response time is less than 1us, short circuit latch protection breakdown protection, under-voltage protection, overtemperature protection, and rotor stall protection are provided through VDS sensing
Application
  • Lawnmower
  • Mowing robot
  • Sweeping robot
  • Wireless handheld garden tools
  • Wireless power tools
  • Wireless vacuum cleaner
  • Electrical pumps and fans
  • Appliance: Compressor