Need a circuit to increase current capacity of 0-10V signal

Let me preface this by saying that I am electronics novice. I can solder and understand basic electronics and am willing to learn. Circuits in general have been very difficult for me to understand so please forgive any mistakes I make. I would really appreciate any guidance that anyone can give me.

I have a device (aquarium controller) that has several 0-10V filtered PWM outputs to act as signal lines to control different items. These seem pretty well filtered by the aquarium controller, and appear essentially as a nearly flat analog DC voltage on a hobbyist oscilloscope. In this case, the outputs are going to be used to control LED aquarium lights. Each string of lights requires a constant current driver which has 0-10V inputs to control LED intensity. The device in question outputting 0-10V as a control signal can only support 10mA current draw and each of these LED drivers attached to the control signal draws 3.3mA. I need to run many more of them than 3 per channel, however, and that is where my problem is, but increasing current handling to 40-50mA per channel should be fine.

After some hours of googling I've decided to ask here. Am I correct in saying that what I need is a unity gain voltage follower (or buffer) circuit? If so, what is available and will input and output 0V-10V, draw no more than 10mA, and deliver identical input voltage at up to 40-50mA?

Here is a link to a thread I started on an aquarium forum to try to get some help:

https://www.nano-reef.com/forums/index.php?showtopic=228743

Re: Need a circuit to increase current capacity of 0-10V sig

Without going into to complicated solutions you can consider simple voltage follower based on single BJT (NPN) or a complimantary pair (NPN+PNP) .. see attached pictures ..
They both are not ideal circuits, you will be "loosing" some voltage at both ends (≈0.7V is required to turn a transistor on) but they are simple and easy to build ..

IanP
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Thanks Ian. Is there an advantage of one over the next? On a quick web search I found an IC that has a complementary transistor pair that I can use, but am not entirely sure how to wire this on the datasheet or your diagram.

V-in (signal) would be at the base of the transistors right? Is V-out between the emitter of the first and collector of the second? Basically, I'm not sure about anything else either in terms of practically wiring this. The supply voltage, presumably ~12V would be at the top supplying the first collector with ground after the second at the pnp?

Sorry. Told you I was a newb. STS01DTP06 is an IC that I found on the web that has a complementary pair on board, but not sure what to make of all it's specifications for my application. This thing is only 5mm! I think I'd have a difficult time soldering that.

Re: Need a circuit to increase current capacity of 0-10V sig

If you are only sourcing current to the leds you don´t need the PNP transistor as showed in the complementar pair. The NPN (e.g. a BC547) would be enough. The complementary pair can also sink current but I think you don´t need it. Just connect the input signal to the base, the Vcc (presumably 12V) to the collector and take the output at the emitter. Don´t forget to place a resistor in series with the leds to limit the current to a safe value.
Regards

Re: Need a circuit to increase current capacity of 0-10V sig

Take a look at the NPN Current Source - Fig.2.1.a in the following appnote:
https://www.tedpavlic.com/teaching/osu/ece327/lab6_dac/lab6_dac_driver.pdf

IanP
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