Motor driver ICs designed for sensorless BLDCs

Renesas Electronics Corp. has introduced three new programmable motor driver ICs for brushless DC (BLDC) motor applications. Claimed as an industry first, the new chips—RAA306012, RAJ306101 and RAJ306102—allow motors without sensors to enable full torque at zero speed, providing improved power consumption, higher reliability, as well as reduced cost and board space.

Enabling full torque at zero speed without sensors is the result of two Renesas innovations: Enhanced Inductive Sensing (EIS) and Motor Rotor Position Identification (MRI). EIS offers stable position detection when the motor is completely stopped. If it is operating at extremely low speed, MRI is used. At higher speeds, the motor driver ICs use conventional methods.

(Source: Renesas Electronics Corp.)

The RAA306012 65-V, 3-phase smart gate driver standalone device can be paired with a variety of microcontrollers (MCUs) from Renesas or other sources. Integrating three half-bridge gate drivers, it can drive up to three N-channel MOSFET bridges, supporting bridge voltages from 6 V to 65 V. The device integrates power supplies to power internal analog and logic circuitry, high-side/low-side gate drivers and a dedicated supply for powering external MCUs.

The RAJ306101 integrates a Renesas RX13T 32-bit MCU with the RAA306012 in a single package. The smart gate driver includes three half-bridge gate drivers, a buck switching regulator and a charge pump for the gate drive voltage, two LDOs for the internal analog and logic circuitry and MCU (3.3-V to 5-V adjustable), three accurate differential amplifiers, a BEMF sense amplifier, three general-purpose comparators and extensive protection functions.

The RAJ306102 is a general-purpose motor IC for 3-phase BLDC motors. It integrates a 16-bit Renesas RL78/G1F MCU with the RAA306012, also offering similar integration benefits.

All three options offer high integration including drivers, power management and current sensing. Adaptive and adjustable dead time improves efficiency, while programmable gate drive voltage enables driving of N-channel MOSFETs and GaN FETs and rich sensing blocks to deliver better accuracy and wide-speed RPM drive. The devices support motor control algorithms such as trapezoidal, sinusoidal and FOC and offer extensive protection functions that improve system safety.

Each gate driver supports up to 0.64-A source and 1.28-A sink peak drive current with adjustable drive strength control. They support BLDC sensor and sensorless motor drives via three general-purpose comparators or a BEMF sense amplifier.

Renesas has combined the new motor driver ICs with complementary components from its portfolio to offer a wide array of Winning Combinations, including a Cordless Vacuum Cleaner and 20-V Cordless Leaf Blower.

The RAA306012, RAJ306101, and RAJ306102 are currently available. While the RAA306012 is available in a 7 × 7 mm 48-pin QFN package, the RAJ306101 and RAJ306102 are offered in 8 × 8 mm 56-pin and 64-pin QFNs, respectively. There are also evaluation kits for each of the new devices.