Reference Design

A system-level evaluation board that combines ROHM's IC and discrete products. We have already solved not only the characteristics of individual products but also the problems that may occur when combining them to build a system, thus contributing significantly to the reduction of development time for our customers.

AC supply, Sensor-less, Three Phase Brushless DC motor drive Reference Design


An evaluation board that enables direct input of AC power to a BLDC motor unit by installing an ACDC converter circuit in the drive circuit for a three phase DC brushless motor (hereafter BLDC motor). This is an evaluation board that enables direct input of AC power to the BLDC motor unit.
Targeting small motors up to 10W class, this evaluation board has a three phase motor driver + ACDC converter (12V output) on one small board.
It is possible to drive a three phase BLDC motor with an AC motor interface.


  • Input AC power supply voltage 90~264V
  • Motor DC voltage 10.4~13.2V
  • Output current 1.0A(max)
  • Sensorless 12V three phase brushless DC motor drive
  • Motor driver: Motor driver LSI
  • Sine wave commutation PWM drive
  • Speed control by DC/PWM input
  • Rotation direction setting
  • Rotation speed pulse signal output (FG, 1/2FG)

Key Specification (Reference design)

Name of boardRMS308NA-008
Input voltageInput AC power supply voltage 90~264V, motor DC voltage 10.4~13.2V
Nb of outputs1A(Max)(depends on current capability of motor driver LSI)
Output voltageSensorless sine-wave commutation drive ( Three-phase brushless DC motor )
EMC perfomanceInput: Control input (DC or PWM), Rotation direction switching.
Output: FG output.


Fan motor products for small ventilation fans, air purifiers, fans, refrigerators and freezers, industrial air cooling equipment, etc.


Reference Board Image

Product in refDesign and related contents

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Design files