SNOSDL1 December 2024 LMG3650R035
ADVANCE INFORMATION
GaN FET is usually used for high frequency soft-switching and the detection of FET current zero-crossing is needed for system control. LMG3657R035 integrates a zero current detection (ZCD) circuit that provides a digital feedback signal to indicate the when the drain-to-source current is positive. When the IN pin signal goes high, the ZCD circuit includes a blanking time tZCD_Blank, to prevent nuisance ZCD triggering during the turn-on transient. Following the blanking period, the ZCD circuit monitors the drain-to-source current. If the current is negative, a pulse-output with a width of tWD_ZVD is set on the ZCD pin after detecting the zero-crossing point, with a delay time of tzc_Det. If the current is positive, the pulse output is set on the ZCD pin immediately, as indicated in the timing diagrams below.