How to organize the power supply of a seven-segment indicator, in which each segment is a chain of series-connected LEDs?

Question

Do it yourself

Good day to all. If the question is from the category "even a schoolboy should know", then I beg your pardon. I recently got into electronics. In general, I needed to build something with the logic of a seven-segment indicator ( just in case, here ), but each "segment" in which is the n-th number of LEDs connected in series. If each "segment" has one LED, then they can be powered directly by the controller. That is, something like this will turn out: But in the case when there are already 3 LEDs in each segment, 5 volts is not enough. So I’m actually interested, but what is the best way to power such a design? The only thing that comes to mind is transistors. That is something like this:Only one "number" is shown here. If you make more of them, then one transistor to the ground is added to each. In my case, there should be 5-6 "digits" and each has about 20 "segments". Total up to 30 transistors for the entire structure. Somehow it looks very impressive. I would like to hear some advice from really knowledgeable people. Thanks in advance.

Answer 1

Firstly, there are ready-made drivers - microcircuits, in which everything is already there for connecting a display.
Second, explore the LED matrix approach. 6 digits, this is 6 familiarity of 8 elements, these are 14 transistors - 8 for cathodes, 6 for anodes (or vice versa). Transistors are in the form of assemblies - the case is like a microcircuit, and inside there are powerful keys. ULN2003 might be of interest to you.
Well, for bipolar transistors, you need to put a resistor between the base and the output of the controller, about two kilo-ohms.