Lithium Multi-Chemistry LVCO - check my stuff to make sure i havent... - Page 1
Forum section: electronics / projects

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 09, 2013, 09:21:33 am
content: It's always good to have a second set of eyes to look over your stuff so I was hoping someone would be kind enough to look over this for me before I go and get some boards made;Schematic;https://dl.dropbox.com/u/677635/battery_monitor_reva.pdfGerbers;https://dl.dropbox.com/u/677635/BATTERY_MONITOR_REVA_GERBER.zipLayout (ORCAD) file;https://dl.dropbox.com/u/677635/battery_monitor_reva.maxBom;https://dl.dropbox.com/u/677635/BATTERY_MONITOR_REVA_BOM%20%282%29.xlsBasically, you have a "tap" at each cell tab, going all the way from gnd/0v to cell8/33.6v the difference between taps is compared to a reference set based on cell chemistry or personal preference, these get fed into a nand then drives a transistor that drives a fet which switches the main pack positive rail.

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 10, 2013, 01:47:23 pm
content: does anyone know if we have any rules against bumping, been here for a bit but still haven't seen any mention of it?

author: Neilm
author_rank: Super Contributor
timestamp: April 10, 2013, 06:40:28 pm
content: Is this to go into a pack as a protection module?Neil

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 10, 2013, 09:03:04 pm
content: It is intended to attach to "hobby" lithium polymer packs (eg, remote controlled modules) so you can use them in place of other batteries, it is "remove able" so you can just unplug one pack, plug another in and hit the button.Some things in particular I wanted checked, when power is initially applied, I do not want it to power on, unless the user presses the button (for safety and other reasons), I think this is how it will behave. I want to test "off" current too, I think since it turns the opamps sect off when off it should be OK.

author: Neilm
author_rank: Super Contributor
timestamp: April 11, 2013, 06:15:43 pm
content: Quote from: peter.mitchell on April 10, 2013, 09:03:04 pmIt is hard to analyse this sort of on/off circuit - you can always have a race condition on power up that you didn't account for - it could be caused by pretty much anything like noise. Orcad is a bit annoying as you can hide the power pins on chips like U7 so I can't see if that has been powered.The trouble is I don't have an Orcad layout viewer so I can't comment on the layout.Neil

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 12, 2013, 04:13:44 am
content: Yeah, I *think* it should be fine, at worst I'll just have to add some pull up/downs, if you want to see the layout, all the gerbers are there so you should be able to put them into an inline Gerber viewer and see.

author: smashedProton
author_rank: Frequent Contributor
timestamp: April 12, 2013, 04:50:03 am
content: Could you please change your picture? Its beginning to irritate me. Thanks

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 12, 2013, 08:15:31 am
content: sure, you should have PM'd me sooner.

author: Balaur
author_rank: Unknown
timestamp: April 12, 2013, 08:57:00 am
content: Here goes my precious contribution to the forum today O0I kinda liked the old picture. Come on, change it back!