I have a VU meter project I am working on using an LM3916 chip and a series of 4 RGB LED's. Each set of colors is varied in intensity by varying the voltage from ~0-15V. Each set of colors draws about 30mA so when all are fully illuminated it exceeds the maximum rating for the LM3916.
So I need to come up with a "relay" of some sort that can be triggered by 12 or 15 volts (preferably) and light up all three colors of LED's each with their independent voltages. For instance R=3.5V G=12V B=15v - but they should all come on at the same time when the "relay" is triggered.
The easy solution is 3 solid state relays - one for each color - but as there are 10 segments of 3 LED's I would need 30 SSRs which is just too expensive (not to mention needing a second 30 for stereo).
My second thought was transistors but I'm not sure how to get them to work correctly - especially with varying voltages.
What I'd like is a SSR with one input but three isolated outputs but such a thing seems not to exist. Ideally I could find a single chip with 10 inputs and 30 outputs but again I can't find anything.