Negative Power Input

Status
Not open for further replies.

nsypid

Junior Member level 3
Joined
Dec 21, 2011
Messages
25
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,442
What do people usually do when designing circuits with negative voltage input ? for example -48 volts ?. What if a external 5 volts used as digital input signal on these circuits ? How do they make sure they won't be ground reference problem ? for example ground reference for -48 volts and +5 volt is different ?
 

Sorry, but your question is not clear at all. What kind of circuit you are referring to ?
 

I used buck converter to convert +48 input to +5 (the plus and minus -48V is switched to +48) to power a microcontroller. suppose i want to use digital input of the microcontroller to detect +5V, i suppose there would be some ground reference problem. should i isolate the input or is there another way to convert -48volt to +5volt ?

- - - Updated - - -

i mean the +5 volt i want to detect with microcontroller is from external sources, which have the same reference ground from -48 volts
 

Many IC's are liable to be damaged if you expose their inputs to a voltage outside the supply rails.

For this reason it may be necessary to level-shift a negative voltage up to the positive.

This can be done in various ways. A resistor network is among the simplest.
 

Status
Not open for further replies.

Similar threads

Cookies are required to use this site. You must accept them to continue using the site. Learn more…