Hey all, I've been working on a MIDI controller project where I need to swap between USB power, an external 5v power supply, and a Lithium-ion battery pack (18650s) to power a Teensy (ofc), some misc. circuitry, and 504 APA102 LEDs.
After looking at this page and various forums about powering things with Li-ion batteries, I've come up with the following rough circuit diagram:
The following chart shows the power routing that I hope to achieve based on which power inputs are active:
Inputs: ______________________ Outputs:
Wherever it says 'USB/Ext'. it just means either should be fine. I guess if I had a preference, it would be nice if it took the power from Ext, but it should be low enough current that USB would be able to supply all necessary power.
I don't quite have a specific question, which is why I'm putting this under Project Guidance rather than Technical Help. I really just want to know if this will work, or if there are any errors. Some concerns I have are that putting boost converters in parallel like I've done won't actually give me 12A of converted power. Also, I should probably put some capacitors somewhere, but I'm not sure where, other than at the external supply. Are my diodes facing the right direction? The page says the diodes will make the Teensy draw power from whichever source is higher voltage, but the external supply and battery might not necessarily be higher voltage than the USB power. Does this mean I have to use the complicated transistor method mentioned? Also, this is the first time I've used Li-ion batteries, so any guidance regarding that is appreciated.
Thanks for reading,
Jaxter
After looking at this page and various forums about powering things with Li-ion batteries, I've come up with the following rough circuit diagram:
The following chart shows the power routing that I hope to achieve based on which power inputs are active:
Inputs: ______________________ Outputs:
USB | Ext. | Battery | Teensy | Circuit | LEDs | |
No | No | No | Off | Off | Off | |
Yes | No | No | USB | USB | Off | |
No | Yes | No | Ext | Ext | Ext | |
Yes | Yes | No | USB/Ext | USB/Ext | Ext | |
No | No | Yes | Batt | Batt | Batt | |
Yes | No | Yes | USB | USB | Batt | |
No | Yes | Yes | Ext | Ext | Ext | |
Yes | Yes | Yes | USB/Ext | USB/Ext | Ext |
I don't quite have a specific question, which is why I'm putting this under Project Guidance rather than Technical Help. I really just want to know if this will work, or if there are any errors. Some concerns I have are that putting boost converters in parallel like I've done won't actually give me 12A of converted power. Also, I should probably put some capacitors somewhere, but I'm not sure where, other than at the external supply. Are my diodes facing the right direction? The page says the diodes will make the Teensy draw power from whichever source is higher voltage, but the external supply and battery might not necessarily be higher voltage than the USB power. Does this mean I have to use the complicated transistor method mentioned? Also, this is the first time I've used Li-ion batteries, so any guidance regarding that is appreciated.
Thanks for reading,
Jaxter