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I have a bipolar analog signal (-2.5 to 2.5V) that I want to shift to 0V to 5V.I could use a few op amps (I also need high input impedance), but I'm trying to minimize component count.I thought it should be a common thing, so maybe someone has made a chip to do just that?Has anyone heard of something like that?
Oh yeah I do love op amps, just curious if there's an easier way.
~10Msps, the signal won't be too fast (or it could be, but I won't be able to see it anyways).
The supply is +-5. +5V from USB, and -5V by doubling (10V), inverting (-10V), then regulating (7905). I'm not actually sure if I need the -5V to be that clean (an inverter alone has really bad output impedance), but I guess it can't hurt.
The inputs (probably 4) go into a voltage divider, then a buffered bipolar video mux. Then I'd shift the voltage to unipolar (just so I won't need 4 level shifters), and that goes into an unipolar differential ADC's Vin+.
I like the virtual ground idea very much, I think I'll do that. If the system is powered by USB, which is powered by the PC power supply, it's isolated right? So I can measure anything except the same PC.
For the circuit you posted, the first amp is a summer, but the second one is a sgn(Vin)? There is no negative feedback.
I'm multiplexing so I can use just one ADC (it only has 1 input), and the microcontroller is not fast enough read from many ADCs at the same time anyways. Also, since it's a parallel ADC (serial/SPI is way too slow), it would also save a lot of traces.I guess I can try to find an ADC with more inputs, too.