R Classroom | Pin compatible within the series, lead angle control function achieves higher efficiency 250V/600V high withstand voltage three-phase brushless DC motor driver IC

Key words

ROHM high voltage three-phase brushless DC motor

Driver IC Features

● Pin compatible

ROHM's high-voltage three-phase brushless DC motor drivers are divided into three series: controller, driver, and controller + driver motor driver , with pin compatibility within each series .

In addition, each series has a product lineup with different withstand voltages, output currents, and drive methods. Customers do not have to design a circuit board for each motor specification, and if the specifications change during the design process, they only need to replace the driver IC on the same circuit board, which can improve development and design efficiency and shorten product launch time.

Below is a block diagram of the functional division of the controller, driver, and motor driver.

● Rich protection functions

In order to withstand high voltage, the product is equipped with many protection functions, which are safer and more reliable. The following is a list of protection functions.

● Super Rake angle control function

(150 degree excitation, sine wave excitation control model)

To maximize motor efficiency, it is ideal to achieve maximum torque by setting the phase of the magnet (rotor) magnetic field and the phase of the coil (winding) magnetic field to 90 degrees.

As shown in the figure below, the product of the phase induced voltage and the phase current is the phase torque, but the negative part of the product (the time period shown in the gray area on the left side of the figure below) becomes negative torque. One way to improve this situation and improve efficiency is to control the phase of the driver output signal relative to the Hall signal.

The negative torque period is eliminated by advancing the phase of the phase applied voltage and matching the phase of the induced voltage and current (green arrow on the right side of the figure below).

The ideal lead angle value varies depending on the motor characteristics, rotation speed, and load torque (current value), so it is necessary to set it to an appropriate value according to the usage status.

ROHM supports models with sine wave excitation and 150 degree excitation. It has a built-in lead angle setting function , which can be set in three ways as shown in the figure below, and higher efficiency can be obtained by setting the lead angle value. The lead value of BM6206FS, BM6207FS, BM6225FS, BM6226FS, BM6224FS, and BM6214FS is set to 0 to +30 degrees, and the lead value of BM6208FS, BM6209FS, BM6227FS, BM6228FS, BM6215FS, and BM6229FS is set to 0 to +40 degrees.

● Built-in power MOSFET adopts PrestoMOS ^™

(Motor driver 600V product)

The 600V withstand voltage motor driver with built-in power MOSFET uses ROHM's own PrestoMOS. PrestoMOS is a super junction MOSFET that significantly reduces losses compared to IGBTs by shortening the reverse recovery time (trr) of conventional super junction MOSFETs while reducing on-resistance and gate capacitance. This can make motor drive efficiency higher in high voltage motor drive applications.

For more information about PrestoMOS, please refer to here .

ROHM Semiconductor Group