Switch-mode DC power supplies represent an important power electronics application area with a worldwide market of several billion dollars per year. Many of these power supplies incorporate transformer isolation for reasons that are discussed below. Within these power supplies, transformer-isolated DC-DC converters are derived from non-isolated DC-DC converter topologies already discussed in Chapter 3. For short, we will refer to transformer-isolated switch-mode DC power supplies as SMPS (switched-mode power supply, sometimes called switcher), whose block diagram is shown in Figure 8.1. As shown in Figure 8.1, these supplies encompass the rectification of the utility supply, and the voltage across a large filter capacitor is the input to the transformer-isolated DC-DC converter, which is the focus of discussion in this chapter. Internally, the transformer operates at very high frequencies, typically upwards of a few hundred kHz, thus resulting in small size and weight, as discussed in the next chapter.
FIGURE 8.1 Block diagram of switch-mode DC power supplies.
8.2 NEED FOR ELECTRICAL ISOLATION
Electrical isolation by means of transformers is needed in switch-mode DC power supplies for three reasons: ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month, and much more.
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
across a large filter capacitor is the input to the transformer-isolated DC-DC converter, which is the focus of discussion in this chapter. Internally, the transformer operates at very high frequencies, typically upwards of a few hundred kHz, thus resulting in small size and weight, as discussed in the next chapter.