Hi
I'v been checking Internet and major IC manufacturers for battery chargers with cell balancing, found none. Amazing, Linear Tech., Maxim, Texas etc does not offer cell balancing in one single chip. I need to charge 2 Li-Ion cells in series. They all say that applications with 2 cells does not require cell balancing, only 4+ it is needed (!?). I disagree, cell balancing is a necessity when dealing with >=2 cell in series. So I stick with my plan. The only problem is that none of those manufacturers support such chip,ok they have multi-cell balancing management chips with uC interaction etc etc, but I dont want to put too much effort into such and spend 10 euros for chips which are meant for balancing and manage 12 cells in packs of 4 for electric cars etc..
Then I came to picture found with two separate ic's, http://www.ti.com/product/BQ29209 and http://www.ti.com/product/BQ2057W
They are charger and balancer. But few questions, how do I connect them together and obviously cell balancing should not fuction while discharging... right?
When the charger is connected to DC input and the actual device is connected to battery, what happens to the charging current measurement because the device takes current aswell along the charging current ? Should the DC input deliver power straight to the actual device connected to the battery while the battery is being charged ? so I need a FET switch to separate then while charging. What could be the proper solution ?
Here is one circuit I found, post did not get any answers so
http://e2e.ti.com/support/power_management/battery_management/f/179/t/285888.aspx