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I'm just looking at the BQ2407x range of Lithium-Ion charging ICs. One part in the range has an extra pin, TD, which disables/enables "charge termination". Here is the functionality description:

enter image description here

Sadly this only goes into what happens if you disable it, but doesn't really say what happens if it is enabled (i.e. I'm guessing normal operation). From my understanding, "termination current" is the current fed into the battery once it reaches the CV stage. As someone semi-new, I can't understand the point of disabling this. So my question:

Why would you want to disable termination current?

The only thing I could find (here) is that you can extend battery life by not charging it to 100% every time, which is what would happen if you disabled any current at the CV stage - but that article encourages reducing termination current, not stopping it entirely. Frankly, the product I'm designing doesn't need to be perfect/have extremely long life, so really I just want to know the consequences of pulling the pin low vs pulling the pin high.

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    \$\begingroup\$ Normally, Li-Ion chargers terminate the CV phase when the current drops below some threshold indicating the battery is "full". The charger is diabled until the voltage drops below some threshold. This prevents overcharging. I don't know why you would want to disable this -- maybe if you have a load attached directly to the battery or something. \$\endgroup\$ – Evan Nov 13 '18 at 0:21
  • \$\begingroup\$ Okay thanks for the concise answer. I figured having it as an option was a bit weird, but I guess that's the point of the 2407x series (each chip has some special characteristic etc.). I'll be sure to keep it enabled since that seems like what is "normal". \$\endgroup\$ – DSWG Nov 13 '18 at 0:31
  • \$\begingroup\$ According to datasheet description, disabling TD also disables a lot of useful safety features. Don 't disable it. This charger's family has 5 chips, and only two have the TD feature. If you are uncomfortable with this pin, use other chips that don't have it. \$\endgroup\$ – Ale..chenski Nov 13 '18 at 1:55
  • \$\begingroup\$ Perhaps for a lead acid battery is better to be charged all the time, disabling this feature \$\endgroup\$ – Marko Buršič Nov 13 '18 at 8:30

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