N Channel Mosfet High Side Switch Circuit

The opposite of the low side switch is the high side switch.

N channel mosfet high side switch circuit.

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 that matter the first circuit drawings that describe the negative vgs using only a positive supply for a p channel mosfet are drawn using n channel mosfets. The n channel high side switch. While you can use a jfet for this circuit an enhancement mode mosfet works better.

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. 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. For an n channel mosfet the source connects to ground and the drain connects to the negative side of the load. Assume the device is initially off.

To switch v with a n channel mosfet use a n channel mosfet with drain connected to v and the load connected to source. 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. This is a simple circuit where a n channel enhancement mode mosfet will turn on or off a light. Based on the circuit it looks like it is a typo where the arrow is pointing the wrong way for a p channel mosfet.

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. In order to do this the gate voltage must be magnified in some way. In the low side configuration the load is connected between the drain and v while the source. There are a variety of configurations for driving the two mosfets with many different applications.