Advice on Creating a Negative Voltage Supply

Projects General Guidance
1

Hi everyone! I am currently working on a project that requires me to generate a negative voltage supply from 0 V to approximately -1.1 V and have that ideally oscillate from 0 to -1.1 V using an Arduino. I was looking at how to best proceed. From looking at the previous threads, I saw that it was not possible to do this via the microcontroller as it can only produce 0 to +5 V. I saw a guide on producing a negative power supply using a 555 timer on all about circuits and attempted the set up using a pwm pin and varying the output with a for loop that would increment gradually from 0 V to 1.1 V using the AnalogWrite command. It did not invert the voltage from 0 to -1.1V, and I got noisy variable negative output when using a multimeter to test.

Is there a way I could vary and oscillate the voltage from 0 to -1.1V? If not, would using the 5 V pin in conjunction with a digital potentiometer to change the voltage output from 0 to -1.1 V be a more feasible option to pursue?

Any help or recommendations would be greatly appreciated. Thank you for your help!

2

See Creating negative Voltage with Arduino Mega 2560 - Introductory Tutorials - Arduino Forum
Adapt for your particular Arduino.

3

You don't say what the current requirement is from this negative supply.

4

Oscillation from 0 to -1.1V is the same as +2V to +0.9V - it just depends on your ground reference. This does smell a bit like an XY problem.

What is your application? Why do you think you need this negative voltage? What is the nature of this desired "oscillation" - waveform, frequency?

An Arduino does not have a DAC but there are ways to create specific voltages, including below the negative and above the positive supply (aka GND and Vcc).

5

Please explain your project. There may be no need for a negative voltage supply.

But your understanding here is also not correct:

I saw that it was not possible to do this via the microcontroller as it can only produce 0 to +5 V.
6

Try this link: https://www.allaboutcircuits.com/projects/build-your-own-negative-voltage-generator/
You will find it and an explanation of how it works. You can use one of the PWM pins for the clock, If you need more power you can use a buffer to drive it. This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!
Gil