Diodes｜Basic

Switching Diode

table of contents

・Structure and Features
・What is Reverse Recovery Time (trr) in Diodes?

Structure and Features

Structure	Symbol	Applications･Characteristics
		Ideal for a variety of switching applications Switching speed：Short reverse recovery time trr

Silicon switching diodes are known for their fast switching speed, small size, long life, and high reliability, making them suitable for various electronic circuits.

These diodes provide switching operation. Supplying voltage in the forward direction will cause current to flow (ON). Conversely, applying voltage in the reverse direction will stop current flow. High-speed switching diodes are normally characterized by shorter reverse recovery times (trr), resulting in better switching performance.

Switch ON	Switch OFF

What is Reverse Recovery Time (trr) in Diodes?

The reverse recovery time trr refers to the time it takes for the switching diode to turn completely OFF from an ON state. Generally, electrons cannot be stopped immediately after operation turns OFF, resulting in some current flow in the reverse direction. Under reverse bias conditions, the diode’s behavior changes significantly, affecting the movement of minority charge carriers and the overall switching performance. The higher this leakage current is, the greater the loss. However, reverse recovery time can be shortened through heavy metal diffusion, material optimization, or by developing FRDs (Fast Recovery Diodes) that suppress ringing after recovery.

Diode Graph - High switching speed →Smaller area (power consumption)→ Less heat

Key Points in Switching Circuits

Trr refers to the time it takes the current to disappear after voltage switches to the opposite direction.
A shorter trr translates to lower loss and higher switching speeds.
When forward biased, a diode allows current to flow through and acts as a closed switch in a circuit.
Switching diodes are specially designed for ‘on’ and ‘off’ functions in a circuit and have a short reverse recovery time, allowing them to transition quickly from the on-state to the off-state, demonstrating their switching function.

【Download Documents】 Transistors & Diodes Basics and Selection

In this handbook, although there are so many types of power devices using Si semiconductors, the basic points are explained, focusing mainly on diodes and transistors for power supply applications. It also introduces the procedure and decision method for transistor selection when designing circuits, as well as application examples that utilize each characteristic and feature.

Download

electronics-basics

Diodes

Basic

Diode Articles ＋

Evaluation

Evaluation of PMDE Compact and Highly Heat Dissipating Package for Si Diodes: Introduction ＋