Effect of phone charger voltage on charging current?

How critical is the output voltage of a mobile phone charger in determining the charging current?

For example, if we were to use a well-regulated power supply as a charger with a low output impedance and no current limiting, will it make a significant difference if the voltage is set at, say 4.8, 5.0 or 5.3, all other thing being equal? Or will the phone's internal circuit compensate for the differences as long as the voltage is above a certain minimum value?

Hi,

There are specifications.
USB, DCP...for example. Download them and read them.

Klaus

Any recommended reading or link(s)? There are many aspects to USB, some of which are not related to power. And though most phone chargers use USB ports nowadays, not all of them do. For example, I still have Nokia 1100 and C2 phones that I still use occasionally. Both use DC barrel jacks.

Besides, my question is about how the phone controls the charging current. I've observed different phones behave differently with the same charger and cable. With roughly the same existing charge level, phone X may draw 1A and phone Y draws 1.6A while phone Z may draw less than 0.5A, all from the same charger with the same cable. I've also seen phones start charging a nearly empty battery very slowly (at ~0.1A), gradually increase the charging rate and then slow down again when it exceeds about 90%. All of these imply that factors other than USB specs are involved.

The battery (nokia) is usually 3 pin device. Open the phone C2 and takeout the battery to see them.

Two for + and -(gnd) and the third for battery capacity indication.

The charger applies the voltage to +ve pin based on the 3rd pin for batt capacity value.
based on that the charger automatically adjusts the charging .

Hi,

USB, DCP is an actual standard for charging supplies. Every comany that uses it has to keep on the standard.
If you have a non standard device, then you sould ask the manufacturer. Because it could be anything: AC, DC, true charging function, power supply function, high voltage, low voltage....

Klaus