What is Functional Isolation?
This video will give an introduction to functional isolation. We will discuss what functional isolation is, why it is used, and a brief introduction to how functional isolation is used in applications by answering the following questions:
- What is functional isolation?
- When is functional isolation needed?
- What are the benefits of functional isolation?
- What are applications of functional isolation?
Resources
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Hello. Welcome to TI Precision Labs. Today, the topic of discussion is, what is functional isolation? We will start with some background material, then discuss the definition and importance of functional isolation. We will then discuss an application in which functional isolation can be used. Finally, we will have some quiz questions at the end.
So let's go over some background of isolation. There are three main types of isolation. We have functional isolation, which ensures the proper functionality of a system. We'll be talking more about this in the next slides.
We have basic isolation, which, while maintaining system functionality, also provides a layer of protection against electrical shock. This added safety feature, even in systems with rare human contact, ensures a safe working environment. Finally, we have reinforced isolation, which accounts for proper system function in a higher degree of protection against electrical shock, equivalent to double insulation.
As you can see, one of the main differences is creepage. Since functional isolation is primarily concerned with the functionality of the system, there is no creepage requirement. This allows for the device to have various creepage sizes.
So what is functional isolation? As mentioned, functional isolation is the minimum isolation required for a system to function properly. Unlike basic or reinforced isolation, functional isolation does not intend to protect from electrical shock. Instead, it protects signals from high ground potential differences to prevent signal inaccuracies.
As mentioned in the previous slide, functional isolators protect the signals against high ground potential differences. Ground potential difference is the voltage between two different circuits. These voltage differences cause a ground loop interference, which can cause errors or signal loss in the data being transferred between two circuits or systems. Functional isolators mitigate this issue by breaking the ground loop and separating the two circuits or systems. This allows for an increase in signal integrity and reduction in data transmission related issues.
There are several benefits to functional isolators. Functional isolators allow for seamless signal transmission, maintaining signal integrity without the consequences of ground loop interference. Functional isolators also have a very small package size.
The image to the right shows the different packages per type of isolation. The REU package for functional isolators uses 80% less board area, allowing users to implement functional isolators in tighter PCB designs. Functional isolators are also lower cost than isolators with basic or reinforced isolation. Now let's look at an application that uses functional isolation.
We have to GaN FETs, high side and low side, each requiring an isolator to communicate from the MCU to the FET. Here, you can see the image to the right in which the ISO6521 functional isolator is a crucial component between the MCU and GaN FET with integrated drivers, allowing for the separation of the ground potentials from either side, and proper signal transmission between the MCU and GaN FET. The ISO6521 operates like a level shifter to avoid feedback and interference from the ground potential difference.
A functional isolator is needed in this application, as the ground H references itself, which can cause interference. Ground L needs to be isolated from ground 1 to allow for seamless transmission of the signals from the MCU. Now for some quiz questions. Please pause the video on each question to take some time and answer the questions. After asking each question, we'll review the respective answers.
The first question, what is ground potential difference, or GPD? Please pause the video and take your time to answer the question. The answer is b. The ground potential difference is the voltage difference between the ground potentials of different circuits.
Now for the second question. True or false, functional isolators in the REU package take up more board space than basic or reinforced isolators? Please pause the video and take your time to answer the question. The answer is false. Applications that require functional isolation typically allow for lower creepage and clearance requirements, enabling smaller packages and a smaller footprint solution compared to a basic or reinforced isolator.
Overall, functional isolators can provide signal integrity and reduce board space in your system. For more information regarding functional isolators, please visit ti.com/isolation. Thank you for watching.
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