Introduction

In this article, we will explain the types and features of digital isolators in detail in the following flow.

1. What is a digital isolator?
2. What types of insulation are there?
3. Where are digital isolators used? (Case study)
4. Features of Onsemi Digital Isolator [Digi_Max]

1. What is a digital isolator in the first place?

A digital isolator is a type of isolation device. Conventionally, there have been optical signal isolation devices (hereafter referred to as "couplers") called photocouplers and optocouplers that have been widely used in various isolation situations. While couplers have many advantages, they also pose challenges in their use. A relatively new isolation device created to overcome this issue is the product category called digital isolators.

There are several technical methods for digital isolators, which will be introduced in the next section.

2. What types of insulation are there?

There are two types of digital isolators: the inductive type (magnetic type) and the capacitive type.

The main challenges for couplers have been temperature dependence and property changes over time. In addition, common mode transient interference also required attention during use.

On the other hand, digital isolators are products that overcome the issues of couplers, but they pose new challenges. The inductive method has problems with EMS and EMI due to magnetic interference. Physical isolation distance is also considered an issue. Like the inductive method, the capacitive method (on-chip type) also has problems with EMS and EMI, as well as the physical insulation distance.

The product that overcomes the physical insulation distance, which is considered to be an issue for both the inductive method and the capacitive method (on-chip type), is Digi-Max manufactured by Onsemi. The insulation method is a capacitive method, but unlike other companies' products, it is a unique point that it is an off-chip type internal structure product. Detailed spec comparison will be explained later.

For now, in the next section, we will introduce specific examples of the scenes and applications in which digital isolators are used.

3. Where are digital isolators used? (Case study)

Below are five examples of scenes where digital isolators are used. There are 3-phase motor control circuits and in-vehicle on-board chargers. In each block diagram, digital isolators are used or can be considered where highlighted "Digital Isolator" or "Optocoupler".

Case 1: 3-phase motor control circuit

Case 2: Network Communication

Case 3: In-vehicle PTC heater

Case 4: Automotive On Board Charger (OBC)

Case 5: Power supply circuit

4. Features of Onsemi Digital Isolator [Digi-Max]

Comparison table 1

Comparison table 2

At the end

Digital isolator [Digi-MAX] manufactured by ONSEMI was planned and commercialized as a product to overcome the problems of existing isolation elements. If you are currently using a coupler or are having issues with a digital isolator, please consider Digi-MAX. For the product lineup, you can check the product page of ONSEMI from the link below.

Inquiry

There are new products and products under development, and there are also products that are not registered in the above link, so if you are interested, please contact us.