On this slide more waveforms can be seen during shut-down. The bypass pin voltage is shown in pink, the feedback pin voltage is below in yellow, and the LinkZero-AX drain voltage is along the bottom in blue, all with a much shorter time base. During the period immediately following shutdown, the bypass pin voltage hardly changes. When the feedback pin is pulled high, the LinkZero-AX device immediately stops switching, but there’s still some activity in the IC as it draws power from the drain pin while waiting to switch again. After 160 cycles of no switching, the LinkZero-AX device goes into the off-mode and the Drain is seen to go completely quiet. In this design, the LinkZero-AX IC shuts down after 1.67 mS, somewhat less than the recommended pulse length of 2.5 mS. In the off-mode, the only voltage still regulated is the bypass pin.