HOW DOES IT WORK?

Fan 5 Click is based on the TC654, a fan speed controller from Microchip that allows you to control and monitor the speed of two DC brushless fans. The TC654 is based on the FanSense™ technology, which protects your application against fan failure and eliminates the need for 3-wire fans. With the TC654, the fan speed can be controlled by its input voltage or the serial interface, allowing for high flexibility. The input voltage of the TC654 represents temperature, typically provided by a chosen internal or external thermistor (selected through an NTC SEL jumper). The TC654 controls fan speed according to the system temperature by pulse-width modulating the voltage across the fan. This method reduces the fan's acoustic noise and extends the fan's working life.

An external N-channel MOSFET, one per channel, controls the fans. Modulating the voltage applied to the gate of the MOSFETs also modulates the voltage applied to the fan. The PWM output can be adjusted between 30% and 100%, based on the TC654's input voltage, or programmed, as mentioned, via the I2C interface to allow fan speed control without needing an external thermistor. The standard I2C 2-Wire interface reads data and configures settings with a maximum frequency of 100kHz.

The TC654 also measures and monitors fan revolutions per minute (RPM), representing a measure of its health. As a fan's bearings wear out, the fan slows down and eventually stops (locked rotor). The TC654 can detect open, shorted, unconnected, and locked rotor fan conditions by monitoring the fan's RPM level. Apart from the availability of this information on the FLT pin of the mikroBUS™ socket, this condition can also be visually detected through the red LED marked with FAULT. The fan RPM data and threshold registers are available over the I2C interface, allowing complete system control.

In addition to the two terminals for fan connections, there is another terminal, VFAN, for an external 12V power supply for FAN1. FAN2 uses the necessary supply from the 5V mikroBUS™ power rail.

This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.

SPECIFICATIONS