Max and min charging current for charging 500mA & 1A devices

[Sunny55]

Hi, i am designing a USB charger for charging a 500 mA device and another charger at 1A for charging 1A device. Before that , i wish to know what is the COMMON VALUES for min and max charging current for 500mA and 1A devices? I just need it to be in the safe side for not damaging da devices.

 

[sky_123]

i am designing a USB charger

What is a USB charger?
A charger that runs from a USB supply, to charge a (say) Li-Ion cell?
A "charger" that does not run from a USB supply, but supplies 5V? In which case it is a 5V supply, not a charger..

 

[Sunny55]

What is a USB charger?
A charger that runs from a USB supply, to charge a (say) Li-Ion cell?
A "charger" that does not run from a USB supply, but supplies 5V? In which case it is a 5V supply, not a charger..

Hi, the USB charger is controlled by an IC where users can set the min and max charging current. I am using it to charge mp3 players and smartphones.

 

[sky_123]

Well, you didn't answer the question clearly, so I'll take a guess and assume you're actually looking to make a 5V power supply with a USB connector,
that can be plugged into smartphones to charge the built-in battery.

In that case, you just need a 5V supply with the capability of supplying 1 or 2Amps, or thereabouts. You needn't concern yourself with the actual charge current, because that will be determined by the target device' load when it begins to charge. You don't have an ability to control that.

 

[Sunny55]

I basically follow the original smartphone usb charger output dc current to set the usb ic's charging current . That should be SAFE ENOUGH to avoid causing damages to the devices connected for charging?