2014年1月20日星期一

MOS tube drive lcd module

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 .

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