Melexis Unwraps Code-Free Single Coil Fan Drivers for AI CPU Systems

Melexis has recently expanded its MLX90412 single-coil fan driver family with the MLX90412-D, a 2.2 The MLX90412-D has been designed for higher-power cooling applications. The new IC targets AI workstation GPUs, data center power systems, UPS equipment, industrial drives, and other systems where larger fans and blowers are needed to handle increasing thermal loads.

The MLX90412-D Plug and Drive single-coil fan driver

The MLX90412-D combines the motor controller, Hall sensor, and driver into a single device while allowing engineers to configure fan behavior without developing firmware. Its 2.2 A current limit supports fan designs up to approximately 18 W at 12 V and 36 W at 24 V, providing enough drive capability for larger single-coil fans that can replace several smaller cooling devices in some applications.

Code-Free Fan Control

A key part of the MLX90412-D is Melexis' "Plug & Drive" code-free integration. Rather than building the fan controller around a separate MCU and developing the associated control software, engineers can configure parameters such as speed curves, frequency-generator (FG) signals, startup behavior, and motor-control characteristics directly on the device.

The MLX90412-D integrates single-coil fan control in a 3 × 3 mm DFN10 package.

This approach is capable of reducing the amount of software development and the number of external components needed for the fan controller. It also gives designers room to adjust motor behavior for a particular fan without moving to a more complex MCU-based implementation. The family supports PWM control as well as open- and closed-loop speed control, with closed-loop regulation specified to ±1.5%.

More Current for Higher-Power Cooling

The 2.2 A current limit is particularly useful for AI workstation and GPU cooling, where increasing power density can require larger fans or blowers capable of moving more air. Instead of distributing cooling across several smaller fans, the MLX90412-D can drive a higher-power single-coil blower, which is determined by the mechanical and thermal requirements of the system.

The MLX90412-D was designed for higher-power fan and blower applications, including GPU and appliance cooling.

Melexis has also revised the motor-control algorithm to provide smoother startup and shutdown behavior and more stable operation at low speeds. Updated proportional-integral (PI) regulation helps maintain control as fan speed decreases, while multiple start/stop profiles allow operation to be adjusted for different fan designs. Commutation options can also be optimized for lower acoustic noise and vibration or for higher torque and efficiency.

Protection and Integration

Protection functions for the MLX90412-D include programmable locked-rotor protection, temperature shutdown, programmable overvoltage protection, overcurrent protection, short-circuit protection, and current limiting. Programmable FG and rotation-detection outputs can also provide additional diagnostic information for the host system. The device also supports low-noise current shaping and is designed to reduce electromagnetic emissions.

The MLX90412 family operates from 3.5 to 32 V and is robust up to 40 V, covering common 5 V, 12 V, and 24 V systems as well as some battery-powered designs. The MLX90412-D is supplied in a compact 3 × 3 mm DFN10 package, less than 1 mm high, which keeps the controller footprint small when board space near the fan is limited.

Access to the datasheet is restricted and is available only via an approved request.

The MLX90412-D extends Melexis' single-coil fan driver family into higher-power cooling applications with a 2.2 A current limit, code-free configuration, and integrated motor-control and protection functions. For GPU cooling, data center power systems, industrial equipment, and other thermally demanding designs, the device gives engineers a way to control larger single-coil fans without adding a separate MCU or developing dedicated fan-control firmware.

All images used courtesy of Melexis.