SNVSBU3 March 2021 LP87702
A short-circuit protection feature allows the LP87702 to protect itself and external components against short circuiting at the output or against overloading during start-up. A short-circuit at the buck converter output is detected during start-up when the output voltage is below 350 mV (typical) 1 ms after the buck converter is enabled. The fault threshold is 150 mV (typical) below the input voltage level for boost. Boost converter is disabled if the output voltage is below the threshold level 1 ms after the boost converter is enabled.
In a similar way, the overload situation is protected during normal operation. If the feedback-pin voltage of the buck converter falls below 0.35 V and remains below the threshold level for 1 ms, the buck converter is disabled. If the output voltage of the boost converter decreases 150 mV below the input voltage level, the converter is disabled after 1 ms. If the output voltage decreases to 2.5 V, the boost is disabled immediately.
The BUCKx_SC_INT and the BUCK_INT bits are set to 1, the BUCKx_STAT bit is set to 0, and the nINT signal is pulled low in the buck converter, the short-circuit, and overload situations. The BOOST_SC_INT and the BOOST_INT bits are set to 1, the BOOST_STAT bit is set to 0, and the nINT signal is pulled low in the boost converter, short-circuit, and overload situations. The host processor clears the interrupt by writing 1 to the BUCKx_SC_INT or BOOST_SC_INT bit. The converter makes a new start-up attempt upon clearing the interrupt, if the converter is in the enabled state.