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If the MOS tube heating is serious, there is a problem with the product designIf the working current is relatively large, it is normal for the MOS tube to have a slight heat, if th...

MOS tube heat, in addition to change a larger MOS, what is the solution?

If the MOS tube heating is serious, there is a problem with the product design

If the working current is relatively large, it is normal for the MOS tube to have a slight heat, if the heat is too large, the design should be improved, you can consider replacing the MOS tube with a larger power, replacing the MOS tube with a smaller internal resistance, or increasing the heat dissipation.

Check whether the MOS tube power is sufficient

Detect whether the maximum current of the circuit through the MOS exceeds or approaches the specification. We should leave a certain margin when designing, and the maximum current through the MOS should not exceed 1\/2 of the specification. For example, the maximum current of the circuit is 2A, we at least choose a MOS tube with a maximum current that can go to 4A or above. If the selected MOS tube rate is not enough, it is recommended to replace a more powerful MOS to improve the reliability of the product.

The internal resistance is very small and the heat is very small

Different brands of MOS or different models of MOS tube, its conducting internal resistance is different, we can consider choosing a tube with smaller internal resistance to reduce heat. The same MOS uses different Vgs, the conduction internal resistance is not the same, the circuit design should set a reasonable Vgs, in order to reduce the heat of the MOS tube

Check the PCB pad design is reasonable

The use of high-power MOS must pay attention to the design of the pad, a reasonable pad can effectively dissipate the heat; When necessary, you can consider increasing the heat dissipation area of MOS or increasing the copper thickness of PCB. For example, change the copper thickness of the PCB from 1 ounce to 2 ounces. Increasing the copper thickness of the PCB will increase the cost, and priority can be given to increasing the heat dissipation area on the PCB.

Add heat sink to MOS tube

Installing a radiator to MOS can accelerate heat dissipation, and it is generally necessary to install a radiator to MOS in applications with high power. When the PCB pad heat dissipation is insufficient, it is necessary to install a radiator for MOS.

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Fan or water cooling. I tried the water temperature and it was okay.


1.ZVS and so on reduce switching loss

2. Replace the Rdson with a smaller tube

3. Heat sink

4. Multiple tubes in parallel instead of one tube (FET can, Diode can not)