Using the PowerBench Whiteboard’s Powerful Analysis Capabilities

June 7, 2018
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The Vicor PowerBench Whiteboard is a valuable tool that many engineers use to create and analyze power system designs. It offers powerful analysis functionality that goes beyond simply determining the electrical performance of a system in steady state.

Let’s input a simple system that takes a 48V input voltage and delivers 3.3V, 5V and 12V into the Power System Designer.

Figure 1 - System Specification in Power System Designer

Figure 1 – System Specification in Power System Designer (click to enlarge)

The Power System Designer identifies several different solutions. In this case we will assume that efficiency is the most important metric for our application and chose solution 2.

Figure 2 - Possible Solutions

Figure 2 – Possible Solutions from the Power System Designer (click to enlarge)

Once we have selected solution 2, we can then click through to a pre-populated Whiteboard to analyze our design.

 

Electrical View

When the whiteboard is open, it is in the electrical view, showing a schematic of the system.

Figure 3 - Whiteboard for Solution Analysis

Figure 3 – Whiteboard for Solution Selected (click to enlarge)

Figure 4 - Whiteboard analysis

Figure 4 – Whiteboard Electrical Analysis (click to enlarge)

The Whiteboard immediately analyzes the system to show the efficiency and power dissipated by each of the power components in the system. The exact voltages and currents throughout the power system are provided and the Whiteboard also produces some key figures of merit in the top left for efficiency, power loss, footprint (of the power components) and solution cost.

We can also see that our system has no alerts, and if we choose to switch the units of measurement from metric to English (square inches) we have that option.

 

Mechanical View

If the size and power density are an issue, we can switch to a mechanical view to see the board area required for both the front end and point-of-load components

Figure 5 - Whiteboard Mechanical View

Figure 5 – Whiteboard Mechanical View (click to enlarge)

Figure 6 - Whiteboard Board Area Calculations

Figure 6 – Whiteboard Board Area Calculations (click to enlarge)

In this view we also get a lot more information about the space required by the power system. In addition to showing the data for front end and point-of-load separately, this view also provides the power density, the power utilization and the maximum height. The figures for footprint are different to those generated previously as in this view the footprint includes peripheral components such as inductors that are required for the Buck and Buck-Boost Regulators.

The power utilization is also a useful figure as in our case we can see that our system has a significant amount of headroom; for example the point-of-load section has a power utilization of just 41.66%.

 

The Power of the Whiteboard: Experimentation and Evaluation

Although the Whiteboard is a great tool to analyze systems designed using the power system designer, its real benefit is quickly determining the impact of changes to the design. By allowing changes to be made and analyzed quickly and easily, it’s simple to experiment with different solutions.

For example, in our design, we know that there is headroom in both the front end and point of load. Let’s assume the current 10W requirement for the 12V rail increases to 50W. Simply clicking on the load allows us to change the current, and then the Analyze button runs the calculations again.

Figure 7 - Changing Load Parameters

Figure 7 – Changing Load Parameters (click to enlarge)

We can immediately see that the amount of power dissipated by the system has increased to 22.39W. We can decide whether or not this is an acceptable amount of heat to remove from the system and if we need to change the thermal design.

Assuming the thermal design remains unchanged, the solution will not increase in volume as the board area obviously hasn’t changed.

Figure 8 - Analysis with Higher Current 12V Rail

Figure 8 – Analysis with Higher Current 12V Rail (click to enlarge)

A similar approach could be taken if more components are used. Let’s assume the requirement for the 12V rail increases to 120W. We can increase the current in the load, and as we know that this Buck-Boost Regulator cannot deliver 10A, we will set up an array of two of these power components. Note that if we didn’t know we needed two components, the Whiteboard would issue a warning highlighting that the Buck-Boost couldn’t deliver sufficient current.

Figure 9 - Create an Array of 12 PoL Components

Figure 9 – Create an Array of 12 PoL Components (click to enlarge)

We can now analyze the new system, which shows that not only has the power dissipation increased, but also the area required by the components is now 15.55cm2 rather than 14.15cm2 that the initial solution needed. We can also select the mechanical view to see the area required when we include the inductors.

Figure 10 - Analysis of Array of Buck-Boost Regulators

Figure 10 – Analysis of Array of Buck-Boost Regulators (click to enlarge)

Using the Whiteboard is easy and provides a great way to experiment with different approaches to determine the best fit for your application in terms of both electrical and mechanical requirements. If you’ve not used this tool, why not create a design in the Power System Designer and experiment on the Whiteboard today. You’ll be amazed how much you can find out in just a few minutes!

 

 

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