Hi, it looks like the MP2665A charger VDD pin is always powered by Vin and/or VBatt. So even when there is no Vin and the system is running on battery NTC divider consuming up to 200uA and draining the battery. Is there any workaround, for example connecting the NTC divider to Vin instead of VDD? Or this charger is not supposed to be used with NTC in battery operated devices? Thank you.
Hi artsemenka,
If you do not need NTC, you can disable it and leave it floating.
Regards,
Vinh Tran
Hi Vinh, thanks for the reply.
I need NTC, but I do not want NTC divider to waste battery energy when battery is not charging. Is there a way to keep NTC divider current only when battery is charging?
Hi artsemenka,
It may be possible to run it off of Vin. However, my concern would be it falsely setting off NTC_HOT. If you have over temperature protection on, the battery FET and LDO FET would be open.
What values are you using for the NTC resistance? Can you try to increase them?
Regards,
Vinh Tran
A good observation, your better IC’s periodically energize the NTC circuit, sample the temperature and then go back to sleep. If the battery temperature is changing by more than a degree a second things have already gone badly wrong. This requires another pin though.
Hi Vinh, thanks. Could you please explain the motivation for monitoring battery temperature when not charging? Is it to disconnect the load if the battery is going too hot/cold? Most batteries have different allowed temperature ranges for charging and discharging so it would disconnect load too early.
In many cases the thermistor is embedded into the battery so I can’t just change it. Also I think it is not reasonable to waste the battery energy regardless of the exact value.