N Channel Mosfet High Side Switch Circuit

Consider the source as the input and the drain as the output.

N channel mosfet high side switch circuit.

Drive circuits for the high side switches are called high side drivers and are more complicated than low side drivers because of the required voltage translation to the supply and because it is more difficult to turn off a floating switch. This transistor connects between v and the load. If you are doing a high side switch pulls the load high or positive to turn it on a p channel device would be chosen. In the low side configuration the load is connected between the drain and v while the source.

While you can use a jfet for this circuit an enhancement mode mosfet works better. Although the p channel mosfet cannot complement the n channel in both on resistance and capacitance simultaneously such combinations as the low threshold p channel tp0610 and the n channel 2n7000. The n channel high side switch. In order to do this the gate voltage must be magnified in some way.

There are a variety of configurations for driving the two mosfets with many different applications. Then the p channel mosfet is used to switch the positive supply to the motor for forward direction high side switching while the n channel mosfet is used to switch the negative supply to the motor for reverse direction low side switching. Used as a high side switch a p channel mosfet in a totem pole arrangement with an n channel mosfet will simulate a high current high power cmos complementary mos arrangement. Conversely if you are doing a low side switch pulls the load low or to ground an n channel device would be chosen.

2 n channel mosfet configured as high side switch you can quite easily see the difference between the high side configuration and the low side configuration. For an n channel mosfet the source connects to ground and the drain connects to the negative side of the load. The n channel mosfet of a buck converter is a high side switch. To switch v with a n channel mosfet use a n channel mosfet with drain connected to v and the load connected to source.