Driven by consumption upgrades, small home appliances such as air purifiers are rapidly evolving from basic functional devices to high-quality, experience-oriented products. As the core component, motor control technology is also advancing—traditional square-wave control is gradually being replaced by Field-Oriented Control (FOC). FOC significantly improves motor smoothness and effectively reduces operating noise, creating a quieter and more comfortable home environment.

As products evolve toward miniaturization, higher integration, and smarter functionality, traditional discrete FOC solutions based on an “MCU + external driver” architecture reveal several limitations, including higher BOM cost, larger PCB footprint, and increased system complexity. These constraints make them less suitable for next-generation air purifier designs.

G32M3101 Air Purifier Solution

Geehy introduces the G32M3101 Air Purifier Solution, a highly integrated motor control solution designed for air purifiers and similar fan applications. The solution is built on the G32M3101 motor control SoC based on a Cortex-M0+ core, integrating a 40 V 3P+3N gate driver and a 5 V/60 mA LDO in a single chip. This “MCU + Driver + Power” three-in-one architecture significantly reduces external components, minimizes PCB size, and lowers overall system complexity and BOM cost.

With the built-in DIV/MULT hardware accelerator, the chip efficiently executes FOC algorithms, enabling smoother motor operation and lower noise. This helps customers design quiet, stable, and high-quality air purifier products.

Solution Board

Solution Overview

•  Simplified Power Supply Design: G32M3101 supports direct 24 V input. The integrated LDO powers the MCU core and drives the power MOSFETs, eliminating complex external power conversion circuits and simplifying the system power architecture.

•  Flexible Speed Control and Feedback: The GTMR (General Timer) captures the frequency of an external PWM input as the speed command, enabling real-time motor speed adjustment. Meanwhile, the BTMR (Basic Timer) outputs a PWM frequency to provide real-time motor speed feedback for accurate monitoring.

•  Intelligent Start/Stop Control: When the user-defined speed command exceeds or falls below a preset threshold, the motor automatically starts or stops.

•  Accurate Current Detection and Control: During operation, phase current is sampled in real time through the chip’s integrated high-performance operational amplifiers and sampling circuits. After coordinate transformation, the torque current magnitude and phase are precisely controlled.

•  Efficient FOC Control Algorithm: The ATMR (Advanced Timer) outputs three complementary PWM signals to drive inverter switching devices, enabling precise motor vector control.

Application Block Diagram

Geehy provides a complete algorithm library, including coordinate transformation, vector control core functions, mathematical libraries, and observer functions. Customers do not need to develop core algorithms, significantly reducing development complexity. A flexible parameter configuration tool allows quick setup of motor electrical parameters and unified calibration parameters. The system supports low-speed/high-speed observer parameter configuration, forward/reverse wind startup, and IPD startup enablement to adapt to various application scenarios.

Motor Operation Current Waveform

Solution Advantages

• Highly Integrated SoC Architecture: A single chip integrates MCU + Gate Driver + LDO, significantly reducing external components, lowering BOM cost, and minimizing PCB footprint—ideal for compact small-appliance designs.

• Dual-Resistor Sensorless FOC Control: Dual-resistor sampling combined with sensorless FOC vector control reduces motor noise and improves rotational smoothness, enhancing the user experience.

• Advanced Startup and Observer Strategy: Supports multi-observer + PLL collaborative operation, including open-loop/closed-loop startup, forward/reverse wind startup, and IPD initial position detection, ensuring stable motor startup under complex fan load conditions.

• Dual Closed-Loop Control: Supports both speed loop and power loop control, enabling real-time motor adjustment to maintain stable airflow even as filter resistance changes.

• Comprehensive Protection Mechanisms: Integrated protections include overcurrent, overvoltage, undervoltage, and stall protection, ensuring real-time monitoring and improved system reliability.

• Quiet and Comfortable Operation: Leveraging the advantages of the FOC algorithm, motor commutation noise is minimized, meeting the strict noise requirements of environments such as bedrooms and study rooms.

G32M3101 Motor Control SoC Overview

•  High-Performance Core with Algorithm Acceleration: Based on a Cortex-M0+ core running up to 64MHz, the chip integrates a 32/32-bit hardware divider (supporting signed and unsigned operations), significantly accelerating division and mathematical processing in FOC algorithms.

•  Highly Integrated Design: Integrates a 40V 3P+3N gate driver and 5V/60mA LDO, enabling direct MOSFET driving and simplified system power design.

•  High-Performance ADC with DMA: Equipped with a 12-bit ADC with up to 2MSPS sampling rate, supporting DMA mode to transfer sampled data directly into memory arrays. Sampling is triggered by the TMR1 TRGO0 signal, reducing CPU load while ensuring real-time and synchronized sampling.

•  High-Precision Analog Peripherals: Includes two operational amplifiers for accurate motor current sampling and two programmable analog comparators for hardware-level overcurrent detection, enabling fast response to prevent motor or chip damage.

•  Rich Communication Interfaces: Integrated UART and SPI interfaces allow easy expansion to IoT modules, PM2.5 sensors, and display panels, supporting diverse functions for smart appliances and small motor applications.

•  Flexible Package Options: Available in QFN32, SSOP24, SSOP28, and LQFP32 packages, accommodating different product standards and PCB space constraints—from ultra-compact designs to standard board layouts.

High-Performance SoC and Advanced Algorithms for

Low Noise, High Efficiency, and Flexible Development

Targeting the air purifier and smart appliance market, the G32M3101 Air Purifier Reference Solution combines a highly integrated SoC with an optimized algorithm library, addressing key challenges of traditional solutions such as large size, high noise, and development complexity. It provides reliable mixed-signal processing and motor FOC control while offering multiple package options to support diverse product designs.

Looking ahead, Geehy will continue advancing motor control technology innovation, supported by a comprehensive ecosystem and full technical support. This will help customers shorten time-to-market and enhance the competitiveness of end products.