level-shifting
Let's say I have a signal where 1v is digital 0, and 4v is digital 1.
I am a little lost how can I use PNP+NPN transistor to have +11..12(for 1) or -11..12V(for 0) output, provided that I have +12/-12 PSU?
UPDATE: This is for low-power MOSFET driver, which has to be done in discreet transistors.
You do not need or want the intermediate voltage represented by V3.Trying to create it as an actual volateg will cause you effort which is not required.
Allow the low side driver to drive a high side driver connected to tje V+ rail.
THEN limit the swing of the high side driver OR the swing that the FET gate sees. Zener diodes are your friends in such cases.
Note that you should zener clamp the INPUT of a driver stage, not the output - so that the driver is not always "fighting" the zener. .
Both circuits invert your input signal. The second one will not work properly.
If you want a non-inverting level shifter you can use this circuit:
simulate this circuit – Schematic created using CircuitLab
When the input is close to 3.3V, the transistor is off and R2 pulls the output up to 5V. When the input is close to ground, the transistor is saturated and the output is equal to the input plus maybe 50mV.
Best Answer
Is this what you mean?