PFD(Power Fail Detector): A PFD monitors the conditions of a power supply, judges the upcoming malfunction, and calculates the time of early warning. The signal of early warning is a 5V TTL signal in general.
PFD(Power Fail Detector): PFD provides a function that monitors the condition of equipment, "t" is the early warning period time that judges the upcoming malfunction. The warning signal is generally a 5V TTL.