In case of VSENSE falls below over voltage release voltage and under voltage detection voltage from over voltage detection state, set release delay time does not occur and OVB immediately switched to "H" when it falls below under voltage detection voltage if transition time is earlier than set release delay time. This is specification of Window voltage detector IC as stated below. OVB is assumed to be already "H" at falling below under voltage detection voltage as described Timing Chart on Datasheet P.9. So, OVB immediately swithed to "H" when VSENSE falls below under voltage detection voltage even though release delay time does not pass.