Lithium protection circuit

[lutkeveld]

I'm working on a PCB that will get its power via a 3S lipo pack. I want it to be a all-in-one module, so protection will be handled by the board.
Requirements: 4A min output, low voltage cutoff, balancing, low BOM count/cost.
Something like this module: http://www.ebay.com/itm/3-cells-4A-w-balancing-Li-ion-Lithium-18650-14450-Battery-Input-Ouput-Protection-/111526325783?pt=LH_DefaultDomain_0&hash=item19f77cae17

Can't find a schematic that matches my requirement. Does anybody have input on this?

[Neilm]

Have a look at the TI website. There are quite a few chips that do this there

[bills]

I bought some of these they work with 3 or 4 cells,seem to be ok and quite small.
http://www.ebay.com/itm/181681937061?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[lutkeveld]

Neilm Only one that seems to fit my requirements at a quick glance is the BQ76920. Don't know what's up with the 'companion controller' though?

Bills, Doesn't fit my requirements and I'm not looking for a ready-made product. I'm looking for a schematic to intergrate into a PCB.

A lot of the blue ebay protection boards that fit my requirements seem to use Seiko IC's, but on their site I can't find them.

[juanfermed]

Hey lutkeveld,

The BQ76920 seems a nice fit and very simple. This is a somewhat old post but if you have not made a choice, you should be able to do it with this one. The "companion controller" is nothing more than an external MCU, whichever you want, that must take care of things like disconnecting the battery when the BQ76920 triggers an alarm. This chip also has some automatic protection functions like overvoltage and undervotage, but other things like over current, temperature protection, short circuit protection and constant monitoring should be done by an external "companion controller".

For the price, it is a nice chip.