cellphone charger circuit

[poxkix]

I mean that your external power supply will just provide the 5v to the internal charger, the charging is controlled by this internal circuit so even if you connect a 5v/10A source the internal charger will still use a small percentage of this current to load the battery.
Lithium battery charges in constant current and constant voltage stages ( ), the value of the constant current is not controlled by you but from the phone manufacturer and the circuit/code he has implemented internally.
7805 has a typical voltage drop of 2v so you will need 7v input min. in order to get 5v output , if the input is lower then the output will drop.
I would suggest four regulators so that the consumption on the regulators is shared too, you will get up to 2v*1A=2W on each regulator so you will probably be OK even without any heatsink but a small heatsink would weep the regulators cooler.

Wew! I understand. Thanks.

Though a few more questions. Which is doing the control for the charging whenever the battery is full, the cellphone or the charger itself? It baffles me but my bet is the cellphone.

I really forgot on how to determine the time it takes for a specific charger to full charge a cellphone. Do you know how? Like 5v .07A with a cellphone battery of 3.7v 950mA

 

[alexan_e]

What you are making in this case is just a power supply for the internal charger so every aspect of the charge is going to be controlled by the charger circuit which is inside the phone.

If the charge was using constant current then you could get a result just by dividing the capacity of the battery with the current value , for example if you charge with a constant current of 1A then a 5AH battery needs 5 hours but in the lithium battery case you are only charging with a constant current in the first stage, then the charging continuous with constant voltage until the current drops to very low levels.
I don't have a calculation for that type of charge.

 

[Audioguru]

Electronic parts like a 7805 voltage regulator IC have a guaranteed maximum output current of 1A, a typical max output current of about 2.1A and a max output currentof 2.4A.

A cell phone has a charger circuit inside that applies the correct amount of voltage and current to the Lithium battery in the phone.
The "charger" for a cell phone is simply a 5V power supply that powers the charger circuit in the phone and also might power the phone while its battery is charging.