N Channel Mosfet High Side Switch Circuit

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.

N channel mosfet high side switch circuit.

Based on the circuit it looks like it is a typo where the arrow is pointing the wrong way for a p channel mosfet. 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. 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. In order to operate a mosfet as a switch it must be operated in cut off and linear or triode region.

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. For an n channel mosfet the source connects to ground and the drain connects to the negative side of the load. This is a simple circuit where a n channel enhancement mode mosfet will turn on or off a light. 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. The opposite of the low side switch is the high side switch. 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. Assume the device is initially off.

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. This transistor connects between v and the load. The n channel 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.