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A power MOSFET is a specific type of metal–oxide–semiconductor field-effect transistor (MOSFET) designed to handle significant power levels. Compared to the other power semiconductor devices , such as an insulated-gate bipolar transistor (IGBT) or a thyristor , its main advantages are high switching speed and good efficiency at low voltages.
Overdrive voltage, usually abbreviated as V OV, is typically referred to in the context of MOSFET transistors.The overdrive voltage is defined as the voltage between transistor gate and source (V GS) in excess of the threshold voltage (V TH) where V TH is defined as the minimum voltage required between gate and source to turn the transistor on (allow it to conduct electricity).
In most circuits, this means pulling an enhancement-mode MOSFET's gate voltage towards its drain voltage turns it on. In a depletion-mode MOSFET, the device is normally on at zero gate–source voltage. Such devices are used as load "resistors" in logic circuits (in depletion-load NMOS logic, for example).
The drawback of connecting a MOSFET in series is that it has to carry the main thyristor current, and it also increases the total voltage drop by about 0.3 to 0.5V and its corresponding losses. Similar to a GTO , the ETO has a long turn-off tail of current at the end of the turn-off and the next turn-on must wait until the residual charge on ...
The application of a negative gate voltage to the p-type "enhancement-mode" MOSFET enhances the channels conductivity turning it “ON”. In contrast, n-channel depletion-mode devices have a conductive channel naturally existing within the transistor.
An N-MOSFET/IGBT needs a significantly positive charge (V GS > V th) applied to the gate in order to turn on. Using only N-channel MOSFET/IGBT devices is a common cost reduction method due largely to die size reduction (there are other benefits as well). However, using nMOS devices in place of pMOS devices means that a voltage higher than the ...
If the MOSFET is an n-channel or nMOS FET, then the source and drain are n+ regions and the body is a p region. If the MOSFET is a p-channel or pMOS FET, then the source and drain are p+ regions and the body is a n region. The source is so named because it is the source of the charge carriers (electrons for n-channel, holes for p-channel) that ...
Compared to the MOSFET, the operating frequency of the IGBT is relatively low (usually not higher than 50 kHz), mainly because of a problem during turn-off known as current-tail: The slow decay of the conduction current during turn-off results from a slow recombination of a large number of carriers that flood the thick 'drift' region of the ...