Npn High Side Switch. The way around this is not usually to use an extra high voltage supply that goes to 06 V or more above the upper rail but rather to use a floating supply that is referenced to the emitter. The load was connected to the power source and an NPN transistor acted as a switch to ground.
In a P-channel device the conventional flow of drain current is in the negative direction so a negative gate-source voltage is applied to switch the transistor ON. I have been using a low side switch similar to first picture below typically with NPN type. I saw a suggestion on using a PNP for switching a load on the low side with the collector grounded emitter following the input first diagram as opposed to the high side.
Figure 8-1 shows the difference between high and low side switching.
Figure 8-1 shows the difference between high and low side switching. On the other hand the NPN low-side switch is similar to the common-emitter amplifier which can have voltage gain. Transistor as a Switch. The NPN transistor ZXTN25050FHTA is only really suitable for a low side switch you have it in the high side which is the ideal way to have a 3V3 logic chip switch a load connected to 5V.
