Contents
How does MOSFET control current?
When the MOSFET turns on, inrush current IRUSH flows to charge this capacitor. This inrush current is reduced by increasing the series gate resistor Rgate. When the gate resistance increases, the rising output current becomes less pronounced.
Why don’t we use the body diode of a MOSFET?
While the body diode is in reverse recovery, its drain-source voltage rises. This behavior can cause a false turn-on of the internal parasitic NPN bipolar transistor, destroying the MOSFET. There is really only one disadvantage of having no body diode: higher reverse voltage drop.
What is the function of body in MOSFET?
The body effect is the threshold voltage variation due to the bulk/source voltage. To cancel the body effect you need to tie both S and B to the same potential.
What is the body diode of the power MOSFET?
Unlike virtually every other active device, the power MOSFET is unusual in that its schematic symbol includes a parasitic device – the body diode. The body diode is intrinsic to the device’s structure.
Why are power MOSFETs used in integrated circuits?
The design of power MOSFETs was made possible by the evolution of MOSFET and CMOS technology, used for manufacturing integrated circuits since the 1960s. The power MOSFET shares its operating principle with its low-power counterpart, the lateral MOSFET.
What makes a MOSFET able to block only one direction?
The connection of the P implantation to the source metallization shorts the base of the parasitic transistor to its emitter (the source of the MOSFET) and thus prevents spurious latching. This solution, however, creates a diode between the drain (cathode) and the source (anode) of the MOSFET, making it able to block current in only one direction.
The additional factor involving λ, the channel-length modulation parameter, models current dependence on drain voltage due to the channel length modulation, effectively similar to the Early effect seen in bipolar devices. According to this equation, a key design parameter, the MOSFET transconductance is: