Three-phase BLDC motor gate driver achieves FET heat reduction while suppressing EMI

ROHM has developed the BD67871MWV-Z, a three-phase BLDC motor gate driver for medium voltage applications (12V to 48V systems). By including its proprietary gate drive technology TriC3, it greatly decreases FET's switching loss while maintaining low EMI – traditionally a trade-off in motor driver ICs.

Motors account for approximately 60% of global electricity consumption – making control technology, which affects energy efficiency, increasingly critical. In 12V to 48V motor drive applications, a simple configuration where an MCU controls three gate drivers has been the mainstream. However, in recent years, demands for high efficiency and precise control have grown, accelerating the adoption of solutions combining an MCU with an integrated three-phase motor driver. Further, a technical challenge in three-phase motor drivers has been the trade-off between power consumption reduction and noise/EMI reduction.

The driver features the company's proprietary Active Gate Drive technology, TriC3, which rapidly senses voltage information from the external power FETs and adjusts gate drive current accordingly in real-time. This greatly lessens FETs' switching loss (and hence heat generation), FET power consumption during switching, while simultaneously suppressing ringing to achieve low EMI.

Compared to the company's conventional constant-current drive products, TriC3 gate drive has been demonstrated in actual motors that FET heat generation by approximately 35% while maintaining equivalent EMI levels. Also, the BD67871MWV-Z adopts a UQFN28 package and pin layout, which are typically used in motor driver ICs for medium-voltage industrial equipment applications, contributing to decreased engineering effort needed in circuit modifications and new designs.

The company also offer general-purpose motor drivers (BD67870MWV-Z, BD67872MWV-Z) with the same package and pin configuration as the new product, designed for constant-voltage drive. From general-purpose types to the value-added types featuring the new TriC3, the company offer a comprehensive product lineup to support a wide variety of applications and use cases.

Application examples include:

• Industrial Equipment: Various motors such as electric drills/drivers and industrial fans.
• Consumer Appliances: Various motors used in vacuum cleaners, air purifiers, air conditioners, ventilation fans and E-bikes (electric-assist sports bicycles).