Negative voltage from positive

[DimaA]

I need to convert the +5v to -5V, using some simple, not complicated method. Is it possible?

 

[House_Cat]

It depends on how much current you need. For low current applications, there are many ways to invert the voltage with switched capacitors:

https://www.aaroncake.net/circuits/vinvertr.htm
**broken link removed**
**broken link removed**

If you need high current, you are going to have to use a more complex approach. You will need to use a switched mode power supply using an inductor or transformer. You will have to convert the +5v to AC, boost the voltage to account for circuit losses, then regulate it back to -5vdc. If you need high current, how much do you need? Your requirements will dictate the best approach.

 

[shusha]

You can get little more current from MAX660. It gives around 100mA's.

__
Tomislav.

I watch grey clouds gather over my islands
first snow falls brings down white silence.

 

[wholx]

hi

i don't know what your application is, but i think in many cases a negative voltage could be avoided by a good design with only positive supply. if it's possible, this should be the simplest way.

 

[jshroff]

It depends on how much current you need. For low current applications, there are many ways to invert the voltage with switched capacitors:

https://www.aaroncake.net/circuits/vinvertr.htm
**broken link removed**
**broken link removed**
If you need high current, you are going to have to use a more complex approach. You will need to use a switched mode power supply using an inductor or transformer. You will have to convert the +5v to AC, boost the voltage to account for circuit losses, then regulate it back to -5vdc. If you need high current, how much do you need? Your requirements will dictate the best approach.

I have built the https://www.aaroncake.net/circuits/vinvertr.htm
circuit and there is a small error in there. Pin 7 needs to be connected to the common connection of R2 & R1 and current R2 end connected to pin 7 needs to go to pin 8.

 

[watersky]

that's right, circuit used should be decided by your require. you can use capacity and switches,and you can also use dc/dc circuit.

 

[DimaA]

I don't need a high-current components, 20 mA would be enough for me.
Unfortunately, I can't get not LM828 nor ICL7660 or MAX660 in my local stores.
The 555 circuit seems to be nice, but does it give stable output voltage?
Are there any other options?

 

[shmoib]

u can try regulators;

7805 for +5V
7905 for -5V