As a module product, the power module has high volume requirements. If you only rely on the internal design of the power module to meet the requirements, the volume of the product will be very large and the cost will be very expensive. Power can be found in almost all electronic products The trace of the module, but few people realize that the power module will have a fever, so what are the reasons for the heat of the power module? Enter, the editor will show you the reason for the fever!
Touch the surface of the power module, warm, the module is broken? ! Slowly, there is a little fever, just because it is working hard. However, high temperature has a great influence on the reliability of the power module! We must devote ourselves to thermal planning to reduce the temperature rise of the power supply surface and internal devices. This time, we took a peek at the thermal planning of the power module.
High temperature greatly affects the reliability of power modules with high power density. High temperature will cause the life of the electrolytic capacitor to decrease, the insulation characteristics of the transformer enameled wire to deteriorate, the transistor to be damaged, the material to thermally age, and the solder joint to fall. Statistical materials indicate that the reliability of electronic components decreases by 10% every time the temperature of electronic components increases by 2°C. Regarding the thermal planning of the power module, it includes two levels: reducing losses and improving heat dissipation conditions. A
1. Loss of components Loss is the direct cause of heat generation, and loss reduction is the root cause of heat reduction. Some manufacturers on the market wrap the heating element inside the module, so that the heat cannot be dissipated. This method is a bit of a cover. Reducing the loss and temperature rise of internal heating elements is the last word. The key components of power module thermal planning are generally: MOS tube, diode, transformer, power inductor, current limiting resistor, etc. The losses are as follows: 1. MOS tube loss: conduction loss, switching loss (registration loss and turn-off loss); 2. rectifier diode loss: positive conduction loss; 3. transformer, power inductance: iron loss and copper loss ; 4. Passive devices (resistance, capacitance, etc.): ohmic heat loss.