A Brushless Direct Present (BLDC) fan controller design to implement thermal velocity management in BLDC followers.
Over current years, there was a big development in information processing gear characterised by compact measurement, elevated processing energy, and better velocity. Nevertheless, these efficiency enhancements have elevated demand for enhanced cooling capabilities, particularly in cooling followers. These necessities embody variable velocity management to minimise noise ranges and preserve vitality, environment friendly thermal administration, safety in opposition to mechanical put on, and fault prevention. NXP has launched the reference design for Brushless Direct Present (BLDC) fan controllers, presenting an answer for implementing thermal velocity management in BLDC followers. The design makes use of a easy velocity management algorithm that successfully manages the fan’s velocity in widespread eventualities prioritising components like noise discount, vitality effectivity, thermal administration, and fault safety.
The reference design is predicated on the 8-pin MC68HC908QT2 microcontroller unit (MCU) that provides a spread of management functionalities to the design. These embody auto-thermal velocity adjustment, motor-lock safety, alarms for over-temperature and motor-lock situations, in-circuit programming for firmware upgrades, and handbook velocity adjustment. The BLDC fan controller design consists of a BLDC fan, Corridor impact sensor, MCU, regulator, transistors, thermal sensor, and buzzer. The basic functioning entails the MCU initiating the BLDC fan by driving the transistors. On the similar time, the Corridor impact sensor detects the fan’s place and alters the logic degree accordingly. Utilizing the indicators from the Corridor impact sensor, the MCU regulates the fan drive by way of a course of referred to as commutation. The fan’s velocity is set by the enter obtained from an exterior thermal sensor. Based mostly on this thermal sensor enter, the MCU adjusts the off-time interval accordingly.
The BLDC fan is powered by a regulated 12V, 1A energy enter. The piezoelectric buzzer is used within the motor-lock alarm circuit to detect temperature. A 350Hz, 15% responsibility cycle tone is used for the alarm circuit. To stop over-current points, the design features a motor-lock safety circuit that halts the motor when the software program detects a no Corridor sign state lasting longer than 100ms. Further capacitors and diodes are added to the design to filter increased voltage spikes. Temperature versus velocity mapping is an integral a part of the design, accounting for variations in software cooling necessities, thermal sensor traits, and motor traits. The firmware incorporates a thermal velocity profile mapping with 256 steps, permitting simple customisation to satisfy particular person necessities.
This reference design has been examined by NXP. It comes with a Invoice of Materials (BOM), schematics, Printed circuit board (PCB) structure, and so forth. You’ll find further information concerning the reference design on the corporate’s web site. To learn extra about this reference design, click on right here.
