The schematic top shows no internal reverse polarity protection. If you connect input voltage backwards, the parasitic body diode of the pass transistor will conduct, destroying the regulator. Always add a series protection diode on the input.
: If a specific rail (like 3.3V) is missing, low voltage may be injected to identify overheating components using thermal imaging or touch. Documentation & Resources lac781p schematic top
Typically uses the bq24725A (labeled bq25A) to manage power input and battery charging. The schematic top shows no internal reverse polarity
This "top-level" documentation is essential for technicians performing board-level repairs, such as fixing "no power" issues. : If a specific rail (like 3
Pressing the button should cause a voltage drop (typically 3.3V to 0V ) on the specific trigger pin, signaling the Super IO to initiate the full power-up sequence. Troubleshooting "No Power" Symptoms