Reading time ( words)
Today, most of our printed circuit boards have at least a few DC-DC converters, and some boards have many. We have a large choice when it comes to deciding what to use: we can design and build our own converter from discrete parts (called voltage regulator down or VRD) or we can buy one of the off-the-shelf open-frame or fully encapsulated voltage regulator modules (VRM).
For low currents we can use linear regulators; for medium and high current we are better off using a switching-mode topology. Whatever circuit suits best our needs, chances are that we want to keep the output voltage regulated against changes in input voltage and load current, which in turn calls for one or more internal control loops.
There is a well-established theory to design stable control loops, but in the case of power converters, we face a significant challenge: each application may require a different set of output capacitors coming with our loads. Since the regulation feedback loop goes through our bypass capacitors (shown as a single Cout in Fig. 1), our application-dependent set of capacitors now become part of the control feedback loop. Unfortunately, certain combination of output capacitors may cause the converter to become unstable, something we want to avoid. This raises the need to test, measure and/or simulate the control-loop stability.
To read this column, which appeared in the June 2015 issue of The PCB Design Magazine, click here.
Andy Shaughnessy, PCB Design007
At PCB West, Zuken shared a booth with Nano Dimension. Zuken has been working with Nano Dimension for some time, and adding support for 3D printing and nanotechnology to its design tool platforms. I sat down with Zuken’s Humair Mandavia and Nano Dimension’s Simon Fried to learn more about this alliance, and to find out more about this odd-looking box being demonstrated in Zuken’s booth.
Andy Shaughnessy, PCBDesign007
Nine Dot Connects has certainly blazed an interesting trail. The company started out as an Altium reseller, but in less than a decade, Nine Dot Connects has also become a design service bureau and a provider of PCB design instruction, training, and consulting services. I recently interviewed Paul Taubman, technical services director for Nine Dot Connects. We discussed the company’s expansion from VAR to service bureau and content provider, and the changing landscape of PCB design instruction.
Pete Starkey, I-Connect007
Pete Starkey continues with his review of the AltiumLive PCB Design Summit held recently in Munich, Germany. The second day commenced with a new product launch. “Working together is hard” it read on the screen. Statistics indicated that 33% of new products were late getting to market, of which 28% were late due to insufficient collaboration, and up to 50% of potential revenue could be lost through being late to market. Then the screen read “NEXUS makes it easy!”