Compared with the bipolar transistor is generally believed that the MOS conduction current is not required , as long as the GS voltage is higher than a certain value , it. This is very easy to do , but we also need to speed.
Can be seen in the structure of the MOS transistor , parasitic capacitance between the GS, GD, and the driving MOS transistor , in fact, is to charge and discharge the capacitor .Tsingtek TFT LCD
Displays Charging the capacitor requires a current because the capacitor to charge the capacitor can be instantly seen as a short circuit, so the instantaneous current will be relatively large . Select / design MOS tube drive the first to note is to provide instantaneous short circuit current size.
Note that the second , NMOS commonly used in high-side driver , need to be turned on when the gate voltage is greater than the source voltage. The high-side driver MOS transistor is turned on when the source voltage and the drain voltage (VCC) the same , so when the gate voltage than VCC big 4V or 10V. If the same system , to get larger than the VCC voltage , the boost circuit is necessary to specifically . Many motor drives are integrated charge pump, it should be noted that the choice of suitable external capacitor to get enough of the short-circuit current to drive the MOS transistor .
Said above 4V and 10V is a common turn-on voltage MOS tube , of course, need to have a certain margin design. And the higher the voltage , the faster conduction , conduction resistance is smaller. Now there are smaller turn-on voltage MOS works in different areas , but in 12V automotive electronic systems, general 4V conduction suffice.
MOS tube drive circuit and loss , you can refer to Microchip 's AN799MatchingMOSFETDriverstoMOSFETs. About it in detail ,
MOS tube application circuit
MOS transistor is the most significant characteristic of a good switching characteristic Tsingtek lcd display
2x16, which is widely used in the electronic switching circuit needed , such as switching power supplies and the common drive motor , there are lighting dimming .
A liquid crystal panel section of the module (LCM): panel process can be divided into three stages, first semiconductor processes preceding (array), that is, the transistor is a thin film layer on the glass substrate made, compared with the middle of the liquid crystal filling assembly process (cell), that is, the color filter layer of glass and glass film transistors, together, poured into a liquid crystal intermediate.
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