LED Controller PCB Design Feedback/Suggestions Request

Thread Starter

devonullo

Joined Feb 27, 2021
1
Hi there,

Main Question
I'm hoping to get some feedback on this PCB design and the overall design, because this my first real electronics project. Also, I have several questions about feedback I received on ESE.

Background
I'm aiming to make an instrument for my brother, and since I've been wanting to get a little deeper into learning electronics, I thought it would be fun to make my own PCB as part of that. The instrument is inspired by both the CRTelecaster and Fan-Bass from Electronicos Fantasticos, and the basic idea to use an LED POV display instead of a laser-cut wood disk for the blades of a fan, that way the notes produced can be changed programmatically. The way I'm hoping to accomplish this is by using a Teensy 4.1, some TLC5948 LED controllers, some AD9833 Function Generators and a lot of programming to have an LED display that varies the colors to produce notes, similar to the Factory Fan Bass I mentioned above. More details can be found in my Electronics Stack Exchange post. I will attach both schematics and PCB layouts for this post.

I've reached out on Electronics Stack Exchange, but I think that forum sort of lends itself to specific questions and my request is a little more general, so I'm posting here as well.

My Questions (in regards to Kartmans response):

1) If I were to use an RC network instead of ferrite beads (which I'm using on the AD9833s), is it as simple as adding a resistor in series, a capacitor in parallel and choosing R and C to accomodate 20-20Khz signals (since that's what the AD9833s will be outputting)?
2) Do I have too many decoupling capacitors? I've read there should be one for each IC, one for every other IC, etc. and I'm not really sure when to apply what for my situation. Also, why would electrolytic capacitors not be preferred in my case?
3) When are split ground planes (analog/digital) appropriate?
4) If I'm powering this off a wireless power coil, are there any additional steps I have to take to protect from EMI?
5) Why would I need resistors on the GPIO pins? If they're already at the right level I don't understand why you'd need them. Is it to protect it from over-current?

I know this is pretty long list of questions so if you'd rather just drop a link than a long comment I'd be grateful for that as well. Thanks in advance : )

Parts list + Datasheets
TLC5948 - 16 Channel LED Driver
AD9833 - Function Generator
DRV5056 - Hall Effect Sensor
LT1962-3/3.3 - LDO Regulators
Teensy 4.1 - Microcontroller

Pictures

Main Schematic
schematic-1.png



LED Array Drivers (TLC5948s)
schematic-2.png


Function Generators
schematic-3.png


Hall Effect Sensor
schematic-4.png



PCB Back LayerPCB-Back.png



PCB Front LayerPCB-Top.png
 
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