The current low power MOS transistor has a resistance of about tens of milliohms and a few milliohms. MOS must not be completed instantaneously at the time of conduction and cut-off. The voltage at both ends of the MOS goes down and the current flows up. During this period, the loss of the MOS transistor is the product of voltage and current, which is called switching loss.
Usually, the switch loss is much larger than the conduction loss, and the higher the switching frequency, the greater the loss. The large amount of voltage and current at the instant of conduction leads to great losses. By shortening the switching time, the loss of each turn-on can be reduced, and by reducing the switching frequency, the switching times per unit time can be reduced.
These two methods can reduce switching losses. Compared with bipolar transistors, it is generally believed that no current is needed for MOS transistors to turn on as long as the GS voltage is higher than a certain value. This is easy to do, but we still need speed. When the gate is given a positive voltage, holes between the two n -type regions get repelled and allow for electrons to flow between the source and the drain. The majority carriers in NMOS devices are electrons, and they can flow much faster than holes.
Since electrons are faster than holes, NMOSs are also more useful in fast-switching applications. This gives a disadvantage to NMOS s because the accumulation of these contaminants around the gate could turn an NMOS device on when it is supposed to be off. Google serves cookies to analyze traffic to this site and for serving personalized ads. Learn more. Skip to content. Last updated: 10th Nov ' Lets check in details. What is NMOS? What is PMOS?
What is CMOS?
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