Led Drive From Ground but Across Dual Supply

I'm having a lot of trouble coming up with a circuit for turning on two LEDs in a compressor circuit (one for the vactrol and the other for the front panel indicator) and I could use some wisdom here.

The following circuit works fine:



When the input control voltage is 0, the LEDs are off. But when the control voltage is positive, the current is proportional to the control voltage.

The problem with this is that it's for a dual battery device and it drains the positive supply faster than the negative because it sources / sinks current from V+ to ground. Not much but enough to require a fix.

So I need to re-work this circuit so that it sources / sinks from V+ to V- and not ground. Does anyone have a trick for doing that?

Meaning take a positive control signal from 0 to say 10V relative to *ground* but generate a current proprotional to the control voltage (so no non linear amplification) that sources / sinks from V+ to V- and NOT dump / source the LED current to / from ground.

I would be ok with using an op amp at this point. In fact, since I already have 2 elsewhere in the circuit, I would be ok with using 2 more if that helps.

It occurs to me that a differential line driver like DRV135 would work. But I don't need a fancy line driver. Is there a similar part that's cheaper, more common and small? Is there a similar circuit to DRV135 that would be applicable?

Ideas?

Not sure I understand the problem... you actually want to drain both batteries instead of only one?

JR

No, I just don't want them to drain unevenly.

Although the current circuit uses very little power compared to an op amp so I suppose using an op amp would not be productive. Maybe that's what you mean?

For posterity here's the solution:



It basically just duplicates and inverts what the first circuit does but ties the other "input" to ground. Pretty much a "diamond buffer" virtual ground basically.

Although I suppose I'm being ridiculous. I'll just stick with the original circuit. At least then I could remove the batteries and swap them and let them drain the other way and save a few mAh in the process. I must be bored.

4 transistors for 2 LEDs  does not sound like a good solution to me...