Hi Everybody
I used a MOSFET to design a level shifter.
However, this must be adjusted according to this value by receiving an external power source.
For example, if VL = 1V and VH = 4V, the output should be between 1V and 4V




How do you design these circuits?

Thanks!

 

You could use a optocoupler with a push-pull-output.

 

Three resistors:
3k between 5V and output.
3k between 0V and output.
1k between input and output.

 

Three resistors:
3k between 5V and output.
3k between 0V and output.
1k between input and output.

Where are the external VL and VH voltages?

 

Where are the external VL and VH voltages?

I didn’t quite read that right. I’ll go with your solution.

 

This design works, Ian0, but the output can not be loaded by the next stage.

 

This design works, Ian0, but the output can not be loaded by the next stage.
View attachment 292765

No it doesn’t - see @StefanZe ‘s comments: “Where are the external VL and VH voltages?”
VL and VH are arbitrary and are the voltages of an external power supply, which may or may not be related to the 0V of the original power supply.

For completeness it needs to be stated that the said optoisolator needs its diode cathode connected to 0V and a current limiting resistor between anode and input voltage.

 

And VH-VL must not be higher than the maximum rating of the optocoupler output.

 

This design works, Ian0, but the output can not be loaded by the next stage.
View attachment 292765

When the A1 output is low then the R1 and R2 will be in parallel, When the A1 output is high then the R1 and R3 will be in parallel, is that right?

Even doesn't care about the in-parallel value, the Vcc voltage is not 4V, so you can't get the output voltage to be 1V and 4V, is that right?

 

The solution depends upon how fast it has to be. What is the expected highest frequency is has to work with or what is the fastest rise/fall times you are looking for? It also depends on what the output has to drive, that is what does it have to drive. (required source current and sink current of the output).