Motor-Control ICs Integrate Position Sensing for BLDCs

Monolithic Power Systems (MPS) is ramping up its focus on brushless DC (BLDC) motors, promoting highly integrated motor-control ICs that combine position sensing, power management, and protection.

Due to their many advantages, three-phase BLDC motors are becoming the standard in a wide range of electronic systems. Today’s BLDC motors tend to be very efficient, in addition to being lighter and more compact than traditional brushed motors, giving them higher power density. They also tend to have higher reliability, longer operating lives, and low noise.

The tradeoff is increased system complexity. BLDC motors require real-time, low-latency control for stable, quick-response movement and balance.

But as brushless DC motors are tucked into the fingers of humanoid robots, cooling fans in EV battery packs, liquid-cooling pumps for data centers, and other systems that face strict power and space requirements, the complexities are intensifying. These BLDC motors must be compact and light to fit within human-sized joints or densely packed server racks. What poses a key challenge for system designers is delivering more dynamic torque control and further improving power efficiency at the same time as all that.

The Expanding Role of Motor Controllers

As a result, MPS and other companies such as Infineon, STMicroelectronics, and TI are stepping up their focus on motor controllers, which play a central role in maximizing power density and minimizing losses. These devices regulate how fast and how much voltage and current the power stages deliver to each motor phase, directly influencing torque, speed, and overall efficiency. High-bandwidth, low-latency control loops enable stable, fast responses, while high-precision, real-time sensing maintains smooth, accurate motion.

The MP6570 from MPS is a high-performance motor-control IC that runs field-oriented control (FOC) in hardware to accurately regulate the torque, position, and speed of three-phase BLDC motors and permanent-magnet synchronous motors (PMSMs). FOC algorithms are widely used for precise motor control due to their ability to reduce noise and provide stable torque output, which decreases vibrations. The chip is designed to be placed between the main control MCU and the power drivers.

By continuously adjusting the voltage and current based on the angular position of the rotors, MPS said the MP6570 can run motors at the optimum torque and speed depending on the situation, giving them higher efficiency and smoother, quieter operation.

At CES, senior applications engineer Charan Bhamra highlighted MPS’s eMotion smart motor modules, which integrate the motor-control IC with MPS power components on a board directly attached to the BLDC motor (see video above).

Embedded Position Sensor and High-Res ADC Enhance IC

One of its distinct features is the embedded high-accuracy position sensor. It eliminates the need for external sensors to determine rotor position or for high-performance MCUs that run “sensorless” methods of motor control, which can be computationally heavy. The magnetic sensor supports up to 14 bits of resolution at high bandwidths of up to 1 MHz, which are ideal for BLDC motors that require high speed or position accuracy. The device is fully configurable over I2C or SPI and features flash memory to program in parameters.

MPS said the MP6570 brings together all other building blocks of a motor controller, including a high-resolution ADC that enables accurate sampling of the current of each phase of the three-phase motor. The chip delivers more than enough performance with the space-vector pulse-width-modulation (PWM) technology, which has up to 12-bit resolution at a 20-kHz switching frequency. While DC-DC converters require high bandwidth, motor-control algorithms primarily operate on average current, relaxing bandwidth demands.

The device stops short of integrating the power stage itself. Instead, with a configurable switching frequency of up to 80 kHz, it outputs high-frequency PWM signals to external gate drivers and power MOSFETs that physically drive the three phases of the motor.

It adds robust protection features, too, to prevent exceeding voltage and current limits and stop overheating. The module can trigger shutdown procedures in the event of power interruption or fault conditions that may interfere with safe power distribution.

Integration Fosters High Efficiency, Precision

By integrating sensing, protection, and real-time control algorithms into the same chip, MPS said the MP6570 enables more efficient and precise motor operation in a small form factor. The precise and fast-speed regulation features of FOC are key to keeping up with systems that are subject to fast and frequent load changes. Furthermore, tighter torque regulation reduces ripples, resulting in smoother and quieter rotation along with lower power losses.

MPS said the MP6570 is widely used in ultra-compact coreless motors, including those embedded in the joints of industrial robots and even in the fingers of humanoid robots. These systems require, above all, high torque density, efficiency, and rapid responsiveness to mimic human movement. The motors must be compact, light, and efficient to fit inside human-sized joints, but capable of dynamic torque control from delicate wrist motions to supporting the load at a hip or knee.