Damage to power ICs is often caused by input voltage overstress, which occurs when power supplies are hot-plugged resulting in excessive voltage spikes or resonance caused by line inductance and low-ESR ceramic capacitors. An ESD cell at the input of a power IC is damaged when it encounters shock energy that exceeds its energy tolerance level. The EOS energy that causes IC damage is typically several times higher than the normal Human Body Model (HBM) ESD energy. When an ESD cell is damaged, the silicon wafer that serves as its carrier is also damaged. In most cases, the damage of the carrier will directly lead to the abnormal operation of the power stage, causing problems such as through short circuit and burnout of the power stage. ESD cells with foldback characteristics may remain at a voltage lower than the operating voltage after being triggered, which can lead to high current flow immediately after being triggered.