This week’s part is a neat little chip from Texas Instruments. TPS2511 USB Dedicated Charging Port Controller and Current Limiting Power Switch. What this chip is designed to do is handle a bunch of newly developed USB charger handshaking protocols. As many familiar with Adafruit’s Mintyboost and other similar USB chargers for portable devices are aware by now, is that not all devices will charge if you simply give them 5V on a USB connector. Many will expect a particular level on the data lines, like certain i-devices, as documented by LadyAda. And yet others will want data lines to be shorted together to recognize the charger. This chip was designed to handle that automatically and hopefully provide a way to support future devices. Another nice feature is cable drop compensation. With high charging currents, the drop across that 6ft USB cable is no longer negligible. So what this chip does is add a bit of bias current to the feedback pin of a power supply feeding it. By doing that it is raising the output voltage by a predetermined amount to compensate for the drop. This feature activates when a load current exceeds a preset threshold.
Very nifty chip- expect a writeup for a project using it soon. But first we must get the boards back from the fab and see if anything smokes!