SNVSCH2 September 2024 LM65645-Q1
ADVANCE INFORMATION
The LM656x5-Q1 includes a power-good function to simplify supply sequencing and supervision in a system. The power good function can be used to enable downstream circuits that are supplied by the LM656x5-Q1, control downstream protection circuits such as load switches, or to turn on sequenced supplies. The function monitors the output voltage with a window comparator through the FB pin for adjustable VOUT configurations and the BIAS pin for fixed VOUT configurations. The power-good output (PG) switches to a high impedance open-drain state when the output voltage is in regulation. When the output voltage is outside of the ±5% range from the set voltage, the PG pin is driven low (< VOL(PG)) warning the system of an output over-voltage or under-voltage condition. A 114µs deglitch filter on the PG falling edge prevents false tripping of the power good signals during transients. When the output voltage returns within the regulation window, a 2ms filter on the PG rising edge allows extra processing time for the downstream components.
TI recommends a100kΩ pullup resistor from the PG pin to the relevant logic rail not greater than 30V. PG is asserted low during soft start and when the LM656x5-Q1 is disabled.