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Electronics => Beginners => Topic started by: noobfrombd on April 20, 2021, 11:37:07 pm

Title: How smartphone charging power management works?
Post by: noobfrombd on April 20, 2021, 11:37:07 pm

Hi, for a long time I wanted to implement smartphone like power feature in my projects. But after tons of searching on YouTube and Google I can only find Power management IC's. But no one to explain how they manage charger connection. Like if I connect my charger to phone it automatically charges, but if I use the phone at very high load, like gaming on it, the phone provides maximum power to it's cpu and other circuitries, then if some power is left from usb, it provides that to battery. It's like if the circuitry load is its 1st priority and charging battery is 2nd priority. There are also some other features are present on smartphones, such as if I disconnect the usb, there is no sudden power blackout on the smartphone, like there is no switching happening from usb to battery, unlike my pc UPS, which takes some time to switch the relay and for that some time i see my pc restarting automatically during power outage. Laptops also behave like smart phone. But how? I know some people uses 2 diodes to feed usb 5v and 3.7v on the same line, but that's creates more problems than it solves. Like how can I change the battery like smart phone does?  :-\

I just want to power some esp32, STM32 and few other controller projects with batteries. Like my ESP 32 rgb led project has lots of LEDs, so I only power it through usb, no battery system. That's also the case for other projects. I don't want to recharge the battery manually. But I also can't use complex PM IC's. Any help?

Sorry for the trouble, If anything doesn't make sense, please ask me. Thanks in advance. :)

Title: Re: How smartphone charging power management works?
Post by: amyk on April 21, 2021, 12:10:36 am

I recommend studying laptop schematics.

Title: Re: How smartphone charging power management works?
Post by: cortex_m0 on April 21, 2021, 12:27:16 am

Take a look at this issue of LT Journal. It describes the functionality of Linear Tech's "PowerPath" family parts. Other ICs have a similar topology. It's the first article, pp 1-5.

https://www.analog.com/media/en/technical-documentation/lt-journal-article/ltmag_v18n2_jun08.pdf (https://www.analog.com/media/en/technical-documentation/lt-journal-article/ltmag_v18n2_jun08.pdf)

Title: Re: How smartphone charging power management works?
Post by: noobfrombd on April 21, 2021, 04:38:10 am

Thanks cortex_m0. It's a big help. Appreciate it👍