Created: Jun 28, 2015
No description available.
Excessive heat in an environment or in any system can cause problems or damages to the devices within that system. One way of solving that problem is to use a cooling fan to cool down the system. In this way we can guarantee that all devices will perform within its operating temperature range. However another problem may appear because later on you will notice that even at lower temperature, the fan will still operate at its full speed and it is a waste of energy. This circuit solves that problem by adjusting automatically the speed of the cooling fan with respect to the system's temperature.
The circuit operation starts at sensing the temperature level of the system by using a temperature sensor. The output of the temperature sensor will be processed by the MCU 's analog-to-digital converter. After processing the data, the MCU will now control the pre-driver of the MOSFETs that drive the cooling fan with respect to the temperature. The pre-driver used in this circuit is the MC33937APEKR2. It is a field effect transistor pre-driver designed to drive three-phase motors. The MC33937 offers precise control and protection of DC motors with up to three phases. That is why it's ideal to control cooling fan.
The power MOSFET used in this circuit is the AP1RA03GMT-HF-3TR N-channel Enhancement-mode type. These power MOSFETs drive the cooling fan with respect to current it receives from the pre-driver MC33937. This MOSFET can provide enough current to drive motors requiring much higher current than low speed motors. With this circuit, we can be able to regulate a system's temperature and at the same time be able to conserved energy wasted by a constant speed cooling fan.