Important DEMO scheduleld for Wednesday 12/16, please confirm question below ASAP.
I'm using the TPS62260 in a LED driver configuration with aN INA196 to sense voltage across a high-side 100mOhm sense resistor. The applicaiton is not exactly an LED, but just about, i.e. I need to put out just enough votlage to drive 500mA on the output. It's not exactly an LED driver, because when the load draws less than 500mA, I don't really care if DC/DC voltage rises up. The circuit has a few more details, but essentially, I need to clarify 1 detail.
What is the absolute maximum voltage rating for the FB pin? It is not clearly stated in the datasheet.
I need to know this because I have had 2 IC failures on my board. After failure the IC draws more current than it sources to the output, and it gets very hot when Vin increases and I_in heads north. The only thing I can track it down to is when the INA sense loop is broken, the DC/DC converter goes 100% duty cycle to try to catch up. I think the INA part is swinging the output to its max since its input differential (Vin- = 0V and Vin+ = 5V). I do have a voltage divider on the FB pin with the top of the string being driven by the INA part, but at worse case, when the sense resistor loop is open, I think we are putting ~3V on the FB pin even after the voltage divider.