The SG6520A is designed to provide the supply voltage, current supervisor, remote on/off (PSON), power good (PGO) indicator, and fault protection (FPO) functions for switching power systems. For supervisory functions, it provides the over-voltage protection (OVP) for 3.3V, 5V, and two 12V; overcurrent protection (OCP) for 3.3V, 5V, and two 12V; under-voltage protection (UVP) for 3.3V, 5V, and two 12V. When 3.3V, 5V, or 12V voltage decreases to 2.3V, 3.5V, and 9V, respectively, the under-voltage protection function is enabled. FPO is set HIGH to turn off the PWM controller IC. The voltage difference across the external current shunt is used for OCP functions. An external resistor can be used to adjust protection threshold. An additional protection input pin provides the flexibility for designing protection circuits. The power supply is turned on after a 48ms delay when PSON signal is set from HIGH to LOW. To turn off the power supply, the PSON signal is set from LOW to HIGH with a delay of 48ms. The PGI circuitry provides a power-down warning signal for PGO. When PGI input is lower than the internal 1.25V reference voltage, the PGO signal is pulled LOW.