This application note presents a basic setup for core independent BLDC fan operation
that can act as a starting point for adding more advanced features and/or control. Some
examples could be:
- Temperature based fan speed
control: This could be implemented by connecting a temperature sensor
via the ADC and set the PWM duty cycle based on the measured value. The duty
cycle could, for instance, be set from a predefined look-up table or by a
control algorithm.
- Closed loop speed control:
This could be implemented by estimating the fan speed from the Hall sensor
signal switching rate and using the value as input to a control algorithm.
- Stall detection: This
could be implemented by detecting lack of Hall sensor signal switching.
- Analog reference input:
This could be implemented by connecting a potentiometer to an ADC input and use
the output value as the set point for a speed or temperature controller, or to
simply set the PWM duty cycle directly.
- Serial communication: By
using the SPI module, remote monitoring and control can be added. This could be
very useful if the fan is to be integrated in a larger system with some higher
level control scheme.