DC-DC converters are needed in industries ranging from rail transportation to defence and aerospace for voltage regulation. At the product launch of DCM2322 DC-DC converter module, Ugo Ghisla, director – power systems applications engineering, Vicor Corp., discusses the various aspects of designing and manufacturing converters, in an interaction with Ayushee Sharma
Q. How has automation impacted product design and manufacturing in the industry?
A. Everything from design and manufacturing to documentation and creation is automated now. After design generation, starting with online simulation, a model is created. After going out for production and then through automated testing, all results and graphs are reported. Then, automated datasheet gets created. There is some individual review, but everything is pretty much automated.
And then there is compliance testing and so forth. But the design itself is quick, scalable and repeatable.
Q. What are the advantages of having high power density in different applications?
A. What is common with all power-based applications is increasing power needs and power densities, which is still cost-sensitive. Higher power density means lower cost because cost is proportional to size in the sense that there is material cost involved. The advantage of having high power density is not just for applications that are space-constrained; there is a long-term advantage of reducing size because there is less copper in PCBs.
Q. What are the various tools used in designing converters?
A. A steady-state simulator, also called a whiteboard, allows you to look at performance of an entire power system in steady state. An online switching simulator can do transient startup simulation, thermal simulation and more. There are thermal tools on which by entering surface or PCB temperature you can calculate different scenarios and operating conditions as well as the temperature that is the worst-case internal temperature for different cases, etc.
Q. How will 5G technology drive the requirement for power?
A. Once 5G starts rolling, we will see an opportunity come up there just because it will require a lot of power and investment, and there is no system from scratch yet. To give an example, the average 4G antenna right now uses about 400W, and a 5G antenna to cover the same area will need 4kW.
Q. What are the issues involved in miniaturisation of converters?
A. The lower the power, the smaller the package. Practically speaking, there are fixed losses once the part is on the gate drive, and that does not scale with power. Topology scales down very well up to a limit but going below that, once you get into lower power than that, you do not get many advantages from the thermal and packaging technology.
For smaller ones that use silicon packages called systems-in-package (SIPs), once you remove the magnetics you can go in a lower profile.
Q. What are the protection options for converters in harsh environments? How is reliability for different applications ensured?
A. There is built-in protection for under-voltage, over-voltage and over-current situations. Short-circuit and thermal protection are also taken care of. Newer packages have more flexible cooling options. Depending on application depth, there is some consideration to make sure it is a high-temperature environment. There are accessories (like heat spreader) for two-side cooling designed to touch the heat-sink at the top or mount at the bottom. This takes heat from the DC-DC converter and brings it up to the side to whatever heat-sink is available.
For the same package and manufacturing approach, reliability is ensured as the process remains the same. For example, products used in the military can go everywhere from drones to missile since these have all been tested as per military standards, like in corrosive environments or under high pressure and high acceleration. For the same package, tested products can then be used for the rail part, too.
Q. What are the unique capabilities of DCM2322?
A. DCM2322 chip family is a lower-power variant of DCM3623 series. The new chip is lightweight and has a more flexible approach. The two numbers here are length and width. So, 2322 means it is 23mm by 22mm. If you have fixed space and need more power for your application, we are getting more power into the same space. You can get the same performance cooling from the bottom that you get cooling from the top. Hence, we are reducing cost yet increasing efficiency.
Q. What are the new areas you are working on?
A. We are now moving forward with products that are more power-dense, more thermally-flexible and more manageable. We are entering the automotive business; we are in 5G migration and, of course, in rail and defence. We also have parts going into satellites in space. Some of our products are designed for sub-one-volt GPUs; for example, NVIDIA has launched 48-volt GPU accelerating artificial intelligence (AI) powered by us.