7.3.4 High Optical Power Protection

There is an additional FET in series of power path connecting with the APD. When the current flowing through the APD exceeds the short protection threshold (set by connecting the resistor from I_SHORT to GND), the on resistance of the FET becomes larger to clamp the current within the protection threshold by lowering the APD bias voltage. It takes typically 0.5 µs for the FET to respond in case of high optical power occuring.

When the high optical power condition releases, the TPS61391 recovers automatically back to the normal operation mode.