In the actual application process, excessive temperature rise often occurs in the MOS tube of the power transformer and the transformer design itself. Today we will start from these two aspects to see how to effectively solve the temperature rise of the switching power supply transformer. High problem.
First of all, from the perspective of the transformer itself, once the temperature rise is too high, it is mainly caused by four problems: copper loss, winding process problems, transformer core loss, and transformer design power is too small. No-load heating is due to the insulation of the transformer or the high input voltage of the transformer. The insulation needs to be rewinded. The high input voltage requires lowering the input voltage or increasing the number of coil turns. If the voltage is normal and it becomes hot when the load is applied, the load of the power transformer is too large and its load design needs to be changed.
In the design process of the switching power supply transformer, the heating of the MOS tube is the most serious, and its own excessive temperature rise is caused by loss. The loss of MOS tube is composed of switching process loss and on-state loss. To reduce on-state loss, you can reduce on-state loss by choosing low on-resistance switching tube. The switching process loss is caused by the gate charge and switching time. Yes, to reduce the loss of the switching process, you can choose devices with faster switching speed and shorter recovery time to reduce. But it is more important to reduce losses by designing better control methods and buffering techniques. For example, using soft switching techniques can greatly reduce this loss.
In addition, there is a possibility that the temperature rise of the power transformer itself will be too high, that is, the aging phenomenon of the transformer itself. When the engineer inspects the transformer itself and the MOS tube and finds no abnormalities, it is necessary to make a comprehensive judgment based on the working time and working life of the transformer.
Post time: Jun-24-2021