Little Question

Hello Everyone,

Does someone here know how to build a single-ended input to differential-ended output circuit without any amplifiers at all?
It would be great if someone could send me a picture of this circuit.

Thank you.
Elad

If the signals are AC a transformer will do the job.

Actually, the signals are only DC.
Do you have an idea how can i do it?

An active phase inverter will do it. Because it does not amplify the voltage (or current) by definition it is not an amplifier.

When you say "amplifier", do you mean Op-Amp? In other words, does this exclude transistors?

It can range from a single transistor phase inverter to an IC op amp.

No, I was referring to:

bq). Does someone here know how to build a single-ended input to differential-ended output circuit without any _amplifiers_ at all?

Should have included the quote, sorry.

To help us understand your requirements, could you explain the purpose & function of the required circuit ?

optocoupler can handle dc

True-ish, but how is that relevant to this conversation?

[Technically, an OpAmp's inputs are actually called "inverting" and "non-inverting". The "plus" and "minus" signs are merely symbolic representations of "inverting" and "non-inverting". It's a misnomer to call the inputs "positive" and "negative".]

I have an accelerometer which have only one output, and because i want to connect it into an ADC with positive and negative inputs, i need a single-ended input to a differential-ended output. The reason i want to build it without amplifiers, is the NSR of those amplifiers. I hope that by building it without it, my circuit will gain less noise.

It would, probably, work just fine if you connected the output of the accelerometer to the "positive" input of the ADC, and connect the accelerometers ground line to the "negative" input of the ADC. If the reason for the differential input ADC is to cancel noise on a length of cable between the accelerometer and the ADC, and the accelerometer gets it's power from the same supply that supplies the ADC, then run separate power lines to the accelerometer. In other words, there would be 4 lines:
1. A line form the ADC positive supply line to the positive connection on the accelerometer (e.g. VDD, VCC, etc).
2. A line from the accelerometer's output to the "positive input of the ADC.
3. A line from the accelerometer ground (i.e. connected as closely to the accelerometers actual, physical ground connection as possible) to the ADC "negative" input.
4. A line from the supply ground on the accelerometer, to the ground (or negative [not to be confused with the "negative" input on the ADC]) supply on the ADC circuit.

When u said ,on the first line u have suggested to connect, "to the positive connection of the accelerometer", u mean to the accelerometer positive power supply?

Sorry, that was a bit ambiguous. Yes, the positive power connection on the accelerometer. I was trying to be "generic" because I don't have a clear picture of what "accelerometer" means. Is it a chip, or is it a chip mounted on a PCB, or is it a set of circuitry on a PCB, or ???

So, my dilemma was how to generically refer to the positive power connection ;)

[I guess I could have just _said_ "Positive power connection" ;]

First, thank u very much for your answers, i appreciate it.
I will try to connect it the way u have suggested, and hopefully it will work that way.
I will let u know if it succeeded.
And by the way, accelerometer is a chip mounted on the PCB.