LI-ION battery charger help

Go To Last Post
5 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I have an interesting design coming up. There are two batteries. An internal LI-ION and an externals LI_ION. Both single cell. The internal battery is charged by the external battery. The problem is that I have had no luck so far finding a LI-ION battery charger IC which can take aprox 2.7V to 4.2V on the input and perform its intended purpose. I certainly can boost the primary battery voltage to what most battery charger IC's require at the input, I would just prefer to not do that with an additonal IC. Anybody know of one out there?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Are you saying the external Li is directly connected to the internal Li and is supposed to charge it ?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

No. The external battery's energy is used to charge the internal battery, yes. But it is not directly connected.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I think you'll end up with two chips, a boost switcher up to 5V and a dedicated charger chip.
Since both of those parts are fairly common, I'd expect it to be a cheaper solution than anything else.

Four legs good, two legs bad, three legs stable.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I am attempting to reduce the number of IC's on the PCB to make it smaller. Hence the search for a single IC that does both the buck boost and charging. I am getting the feeling that this beast does not exist!