BLDC-fan motor driver employs sensorless sinusoidal architecture

Bill Schweber, EE Times - January 19, 2012

The PC fan may be less glamorous than active components are, but managing it and minimizing its power usage are critical to the overall system design, cooling, and runtime. Addressing these issues, Microchip Technology’s MTD6505 stand-alone, resistor-programmable fan motor driver enables the selection of multiple BEMF (back-electromotive-force) coefficient ranges. This feature allows engineers to design in one device to match a variety of three-phase BLDC-fan characteristics. The driver comes in a 0.5-mm-thick, 3×3-mm, 10-pin UDFN package suiting space-constrained applications, such as thin laptops and tiny BLDC fans.

For high energy efficiency and quiet operation with low acoustic noise and mechanical vibration, the MTD6505 includes a 180° sinusoidal drive. As a sensorless driver, the MTD6505 eliminates the need for an external Hall-effect sensor, reducing both cost and board space. It also includes on-chip-protection features to preserve the motor’s life and avoid harmful operating conditions, including thermal shutdown, overcurrent limiting, and lockup protection.

The $59.99 MTD6505 demonstration board will be available this month. It comes with a three-phase BLDC fan and three MTD6505 plug-in modules. A free, downloadable GUI is also available. It simplifies fan monitoring and control with an onboard PIC microcontroller. The MTD6505 motor driver is available for sampling and sells for 57 cents (5000).

Microchip Technology