![]() ![]() MOSFET has positive temperature co-efficient for resistance, this makes parallel operation of MOSFETs easy.So at high frequency applications power MOSFET is the obvious choice. Power MOSFET has lower switching losses but its ON resistance and conduction losses are more.Power MOSFET a operates as a switch either at A or B just like a BJT. Here A indicates fully ON condition and B fully OFF state. A local line intersects the output characteristics at A and B.For given VGS, if VDS is increased output characteristics is relatively flat indicating that drain current is nearly constant.For low value of VDS the graph between ID - VDS is almost linear, this indicates a constant value of on-resistance RDS = VDS/ ID.The magnitude of VGST is of the order of 2 to 3V.ī) Ouput Characteristics: This characteristics shows the variation of drain current ID as a function of drain source voltage VDS. It is seen that there is threshold voltage VGST below which the device is OFF.Thus, power MOSFET can work at switching frequencies in the megahertz range.Ī) Transfer Characteristics: This characteristics shows the variation of drain current ID as a function of gate source voltage VGS. Therefore, time delays caused by removal or recombination of minority carriers are eliminated. Power MOSFET conduction is due to majority carriers.A power MOSFETs actually consists of a parallel connection of thousands of basic MOSFET cells on the same single chip of silicon.This shows that drain current ID is enhanced by the gradual increase of gate voltage, hence the name enhancement MOSFET. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |