Application of Field Effect Transistor

928083047

Application of Field Effect Transistor [Copy link]

When j25, what is the working principle of 12 connection, and 23 connection

maychang

The 1st and 2nd pins of J25 are connected, and the gate of Q9 gets half of the input 9-30V voltage, that is, 4.5V-15V. Q9 is turned on, U75 is also turned on, and the 1st, 2nd, 3rd, and 12nd pins of U76 also get the input 9-30V voltage.

Pins 2 and 3 of J25 are connected, the gate of Q9 is grounded, Q9 is turned off, U75 is turned off, and U76 is not supplied with power.

qwqwqw2088

This is a typical circuit that controls the PMOS tube.

U75 is a P tube, Q9 is an N tube

12 connections, the g pole of Q9 is half of the input voltage, making the Ugs of the NMOS tube>0, Q9 is turned on, the G pin of U75 is low, its Ugs<0, the PMOS tube is turned on, and this provides power for U76.

23 Company, lower level has no power supply

928083047

qwqwqw2088 posted on 2019-8-27 15:20 This is a typical NMOS tube controlling PMOS tube circuit. U75 is a P tube, Q9 is a 12-connected N tube, and the g pole of Q9 is half of the input voltage, making the NMOS tube...

So this circuit just acts as a switch? Doesn't it have any other functions?

maychang

928083047 Published on 2019-9-17 23:05 So this circuit just acts as a switch? It has no other functions?

"So this circuit just acts as a switch? It has no other function?"

It seems to have no other effect.

qwqwqw2088

928083047 Published on 2019-9-17 23:05 So this circuit just acts as a switch? It has no other functions?

Connect 1 and 2, U76 works under MOS control

The 2nd and 3rd stage do not work

The other functions depend on the function of the overall circuit.