How do typical 5V phone charger control charging status?

[zenniz]

Anyone know how a typical 5V phone charger control charging status? A circuit diagram will be useful for explanation.
For example when the phone is fully charged, what happens inside the phone charger?

 

[tpetar]

Anyone know how a typical 5V phone charger control charging status? A circuit diagram will be useful for explanation.
For example when the phone is fully charged, what happens inside the phone charger?

Usually nothing specially happening in "phone charger" its usually just SMPS or small iron transformer based psu. which provide 5V. Real charger IC and charging control are in phone inside. It will be very dangerous to have real charger in adapter called "phone charger". Imagine little LiPo inside phone which expect max 4,20V and you connect 5V from USB port or 5-6-7V from bad car voltage adapter, and all of that on hot and a sunny day.

Li-Po/Li-Ion is charged up to 4,20V*.

You can use power and charger your phone from PC dekstop/laptop USB port which provide 5V on output. Also you can use "car phone charger" which lower car voltage from 12V to 5V. But real charging control is done in phone inside.

Some other devices which use Li-Ion 18650 or similar batteries sometimes in cheaper products have real charger in mains adapter which provide 4,20V on output. This is done to save space in device such as hand torch. But in this situations manufacturer stick big sticker with BATTERY CHARGER notice.

 

[zenniz]

Thanks for clearing my doubt. I always thought that the phone's battery is just the battery alone, didn't know that it has a charge controller inside.

 

[tpetar]

Phone battery contains only small protection circuit which can protect battery from high temp, over current, discharge under lower limit, over voltage during charging. In this situations this circuit disconnect battery from load.

Real charger IC is in phone, soldered on PCB, usually one small IC with one two capacitors, of course all very small.


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