Variable voltage output with 5V input signals

Thread Starter

egraham

Joined Mar 7, 2024
4
Hi, I'm relatively new to circuit design and I have a somewhat unique problem (or so I think). I have two 5V input signals from a microcontroller that I would like to use to control a user selectable output voltage (0-60V) from a DC power supply. Basically, if the user selects a 30V output, the program on the microcontroller will send a 5V signal for a specified duration to get 30V, then a different 5V signal for the same duration to get -30V. (There are also points where there is no signal from the microcontroller and the voltage output should be 0). I would like to do this with transistors since I need a pretty quick response time (no relays). Any ideas of where to start? Or is there a component that could do this much more simply?
 

BobTPH

Joined Jun 5, 2013
9,149
I cannot understand what you want. You say you want to control a 0-60V output via two 5V signals. How does one select what voltage to output? Need more information. It sounds like you might be taking about a PWM signal, is that correct?
 

crutschow

Joined Mar 14, 2008
34,689
the microcontroller will send a 5V signal for a specified duration to get 30V, then a different 5V signal for the same duration to get -30V.
What do you mean "a different 5V signal".
Do you want it to alternate between +30V and -30V each time a 5V signal is seen?
Where is the -30V signal coming from?
 

Thread Starter

egraham

Joined Mar 7, 2024
4
I cannot understand what you want. You say you want to control a 0-60V output via two 5V signals. How does one select what voltage to output? Need more information. It sounds like you might be taking about a PWM signal, is that correct?
Sorry I should have been more clear, one selects the voltage to output by selecting the voltage on the DC power supply. This power supply can then output the +/- of that specified voltage. Yes, similar to a PWM signal. The output would look like this1709836294943.png
 

Thread Starter

egraham

Joined Mar 7, 2024
4
What do you mean "a different 5V signal".
Do you want it to alternate between +30V and -30V each time a 5V signal is seen?
Where is the -30V signal coming from?
Currently the setup has two outputs - when one is 5V the output is positive, when the other is 5V the output is negative. the +/-30V is coming from a power supply
 

Thread Starter

egraham

Joined Mar 7, 2024
4
Sorry I should have been more clear, one selects the voltage to output by selecting the voltage on the DC power supply. This power supply can then output the +/- of that specified voltage. Yes, similar to a PWM signal. The output would look like thisView attachment 317112
Except there are also points in the square wave where the output is 0
 

BobTPH

Joined Jun 5, 2013
9,149
Yes, this is a common circuit, called an H-bridge, often used to control a motor to run in forward or reverse.
 

MisterBill2

Joined Jan 23, 2018
18,986
It seems to me that the intention is that the voltage out should depend on the length of the pulse.
If you want any level of accuracy or repeatability, it will not happen without a really complex arrangement.
So get a microcontroller with a digital to analog output, and then a DC amplifier to boost that voltage to whatever level you want.

AND, an important part of the design process, which comes right after creating the initial requirements, is to determine how the process will work. Adjusting a voltage based on a time is a rather big challenge at the best.
 
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