History

isthatme 5f7c66c363 Designed a simple AC dimmer circuit. (untested)		2018-05-01 03:53:06 -06:00
..
cust_footprints.pretty	Finished schematic for Altoids Power Supply	2017-11-24 09:33:19 -07:00
Gerbers	Made the Uno Switch Shield six headers instead of four.	2017-12-02 21:39:13 -07:00
Altoids-PowerSupply-BOM.csv	Designed a simple AC dimmer circuit. (untested)	2018-05-01 03:53:06 -06:00
Altoids-PowerSupply-cache.bck	Finished schematic for Altoids Power Supply	2017-11-24 09:33:19 -07:00
Altoids-PowerSupply-cache.dcm	Finished schematic for Altoids Power Supply	2017-11-24 09:33:19 -07:00
Altoids-PowerSupply-cache.lib	Rev A possibly complete, need to review to ensure no errors.	2017-11-27 19:23:01 -07:00
Altoids-PowerSupply.kicad_pcb	Started Rev B of Altoids PSU.	2017-12-05 11:37:53 -07:00
Altoids-PowerSupply.net	Rev A possibly complete, need to review to ensure no errors.	2017-11-27 19:23:01 -07:00
Altoids-PowerSupply.png	Exported some PNGs; Added a BOM; Modified a README	2017-12-06 15:50:27 -07:00
Altoids-PowerSupply.pro	Finished schematic for Altoids Power Supply	2017-11-24 09:33:19 -07:00
Altoids-PowerSupply.sch	Rev A possibly complete, need to review to ensure no errors.	2017-11-27 19:23:01 -07:00
BOM.xlsx	Exported some PNGs; Added a BOM; Modified a README	2017-12-06 15:50:27 -07:00
fp-lib-table	Finished schematic for Altoids Power Supply	2017-11-24 09:33:19 -07:00
README.md	Exported some PNGs; Added a BOM; Modified a README	2017-12-06 15:50:27 -07:00

README.md

Altoids Power Supply README

Intro

I saw a tin of altoids at the grocery store the other day. I decided that if I was going to get into electronics I better do at least one project using an altoids tin. Also I really don't have a good power supply (an atx supply with a mess of wires doesn't count), so I figured I'd make a portable power supply with some common voltage rails.

Thus, this project was born.

Main Goals

Battery powered PSU with common voltage rails (for me at least).

Must have features:

5v rail.
3v3 rail.
Battery and a way to convienently charge it (USB)

Wants:

12V rail. (I don't know why)
5V USB output (as a phone charger)

I also wanted to learn about switch mode power supplies, so I used two MC34063s, one for the 5V and one for the 12V. (EEVBlog's tutorial was INCREDIBLY useful). 3v3 works better as a linear supply because you don't have to drop too much voltage.

Li-ion charging is also a new thing for me, so this will be a learning curve.

Rev A

Finished layout, design files are done.

Max current is:

300mA for 5V and 3v3
100mA for 12V

Issues

No silkscreen labelling for what's what.
Unsure if it actually works (haven't received the board/put it together yet)
The 'cutoff' transistor should really be controlled by an NPN switch, the circuit should default off.
Probably should have chosen a different diode (especially for 12v) with higher current capabilities
Component choices are hit and miss, smaller, cheaper components could have been selected (I went with most of my current choices just to make ordering and layout simpler and more consistent).
Double sided load. Ideally all the components (especially surface mount) should be on one side. This comes down to component selection mostly. Not sure how much extra space I have (or could have).
Minimum size you can get of 330uF caps is 6.3mm diam, need to change out this footprint.
Really I should select the components and download footprints from digikey
switch will need to be bodged in

Rev B

I'm starting this right now with the silkscreen corrections, just so I don't forget them again.

TODO

make the cutoff transistor default off.
fix other issues that pop up.