Amplification and DC offset circuit?

[DanTheMan]

So I have a circuit that outputs a voltage between 4 and 7 V at a constant current...this output should go into a circuit that expects a 0 to 15 V input level.

I don't know ahead of time what the output between 40 and 70 will be, the low limit may be 4.5 or 5.0 V and the high limit may be 7.5 or 8.0 V for example.

What needs to happen is that the low limit gets mapped to 0V and the high limit gets mapped to 15 V.

Is there a circuit that can do this without too much pain?

Thank you!

 

[FvM]

What do you mean with "get mapped"? Manual adjustment, some kind of self calibration? As with any specification, required accuracy and long term stability should be told to be complete.

 

[DanTheMan]

For now let's say that it would be a manual adjustment -- using some on-board potentiometers for example.

Also in the first pass, longer term drift/stability/etc. are not important; this is merely because the output of this circuit goes into a DAC and I'd like to use the full range of the DAC for a circuit that will present a smaller range of values (i.e. 'map' the 4 - 7 V output into a 0 - 15 V DAC input).

Thanks!

 

[FvM]

It's basically a subtractor and a gain stage, can be made with one or two OPs. To design a circuit, one should know about the available power supply (single or dual supply, e.g. +/- 15V ?).

 

[DanTheMan]

Assume a single power supply if possible, +15V. Thanks!

 

[FvM]

A simple single OP solution, but it doesn't allow independant adjustment of gain and offset. It's not easy to achieve with single supply I think.