When the MOS is turned on like 2301, is the VDS voltage 0? That is, there is no loss? The simulation shows that there is no loss.

QWE4562009

When the MOS is turned on like 2301, is the VDS voltage 0? That is, there is no loss? The simulation shows that there is no loss. [Copy link]

When the MOS is turned on like 2301, is the VDS voltage 0? That is, there is no loss? The simulation shows that there is no loss.

maychang

It is impossible to have no loss.

The on-resistance of modern MOS tubes can be as low as milliohms, which means that the loss is very small. However, the loss cannot be zero.

maychang

Now that the MOS tube model is known, check the manual of the MOS tube of that model, which must contain the parameter of on-resistance.

qwqwqw2088

MOS tubes all have internal resistance, and if there is internal resistance, there will be loss.

chunyang

The original poster should think like this: If the voltage drop is really 0, it means that the MOS tube has become a superconductor, so superconductivity can be easily achieved, which will completely change the entire industrial civilization of mankind. But since we have not seen various phenomena related to major changes in industrial civilization, it is obviously impossible to achieve a voltage drop of 0, at least not so easily.

QWE4562009

chunyang posted on 2020-4-17 16:23 The OP should think like this: If the voltage drop is really 0, it means that the MOS tube has become a superconductor, so superconductivity can be easily achieved, which will completely change the entire human race...

If the current is very weak, below 1 uA, then the loss is really small.

qwqwqw2088

The internal resistance of SI2301 is 0.145 milliohms

chunyang

QWE4562009 posted on 2020-4-20 08:30 If the current is very weak, below 1 uA, then the loss is really small

If you increase the current significantly, you will find that low loss is completely different from zero loss. Power MOS tubes are equipped with heat sinks, and even external heat dissipation measures are required. Look at the motherboard of a desktop computer. The MOS tubes used in the switching power supply that powers the CPU are equipped with additional heat sinks and arranged on the air outlet of the CPU fan. Some advanced motherboards even use heat pipes to dissipate heat.