Location:Training / Diode conduction time causes switching regulator failure / Diode conduction time causes switching regulator failure

Most circuit designers are familiar with the dynamic characteristics of diodes, such as charge storage, voltage-dependent capacitance, and reverse recovery time. Diode forward conduction time is often not confirmed, and manufacturers rarely give clear regulations. This parameter describes the time it takes for a diode to conduct and clamp to its forward voltage drop.

Historically, this extremely short period of time (measured in nanoseconds) has been so small that users and vendors have largely ignored it. It is rarely discussed and almost never prescribed.

Recently, switching regulator clock rates and switching times have become faster and faster, making diode conduction time a critical issue. A potential difficulty due to diode conduction time is the eventual development of a brief "overshoot" voltage across the diode, which can induce overvoltage stress even if its duration is limited to only a few ns. This causes the switching regulator IC to malfunction. This video will describe a test method to correctly select diodes for switching regulators.