N Channel Mosfet High Side Switch Circuit

While you can use a jfet for this circuit an enhancement mode mosfet works better.

N channel mosfet high side switch circuit.

In the low side configuration the load is connected between the drain and v while the source. This transistor connects between v and the load. 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. The main problem in using an n channel mosfet in a high side switch is that in order for the mosfet to switch off once it has been switched on is that the voltage on the gate terminal of the mosfet must be made higher than the supply voltage.

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. 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. Consider the source as the input and the drain as the output. For an n channel mosfet the source connects to ground and the drain connects to the negative side of the load.

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. In order to do this the gate voltage must be magnified in some way. The n channel mosfet of a buck converter is a high side switch. The n channel high side switch.

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. There are a variety of configurations for driving the two mosfets with many different applications. There s a catch with this arrangement though the mosfet switches on based on the vgs threshold being reached and the source voltage in this arrangement changes between off 0v and on vin. To switch v with a n channel mosfet use a n channel mosfet with drain connected to v and the load connected to source.