Why can't LM324 or LM2904 output more than 3.6V when used as a follower?
Working conditions: 5V power supply, 0-5V signal input.
Working phenomenon: The signal starts from 0V and increases, and it can follow the function below 3.6V, but after it exceeds 3.6V, it will not follow, and only 3.5V can be output. Why is this?
Maira 發表於 October 14, 2020
Consider the voltage drop of the two BE junctions output by the final stage Darlington.
Elli 發表於 October 14, 2020
Rail-to-rail means that the highest and lowest values of the output voltage are vdd and 0, rail-to-rail, just like the cmos inverter is the simplest rail-to-rail circuit because it has no output voltage loss.
Harri 發表於 October 14, 2020
Another reason is the common-mode input limit, because you are a follower, and if the output is 4V, the input is also 4V, which also exceeds the common-mode voltage limit.
Jalon 發表於 October 14, 2020
Two methods, to increase the working voltage, you must use 5V, then add a follower to the output circuit, but the linearity will be affected. Use negative feedback to solve it.
