Dear Sirs;
I'm trying to use the TPS2511 IC for a circuit which should have 5 Volts and maximum 2.1 amp output depending on what the connected device demands.
But I have a series of problems:
I'm using a bench top power supply set to 5V 2A.
First I used a 22.1 k resistor for ILIM_SET pin but when I connected two different android phones, the input current usage jumped to about 210 mA for about 1 second and then went down to zero. When I connected an iPhone 4, the input current usage was stable at 190-210 mA range. In BOTH cases, the output current was ZERO. It seemed the IC was shut down.
I changed ILIM resistor to 36K to make sure the problem was not because of the output current of my power supply was less than the current rating of the circuit. Now when I connected the devices, the input current was at a little bit more than 500 mA but the output current never went upper than 470 mA and ther are always a difference of about 30mA between input and output current.
The other problem is the voltage drop. I should set the power supply at 5.5 to 5.7 volts to get the 500mA input current usage and the output voltage always shows a voltage drop of about 1 volts.
It seems that the devices think that are connected to a normal PC USB.
Help please.
Best Regards,
Ehsan
