As an alternative to a legacy linear regulator, RECOM has introduced a series of low cost, high performance switching regulators with an identical footprint for drop-in implementation. Specifically, the R-78 series is universal for any application and is even ready for use in the IoT where power loss is a substantial concern. To learn more about the advantages of RECOM’s switching regulator, watch the above video that highlights the capabilities of the R-78 series.
To evaluate the difference of the R-78 series, over the outdated LM78 linear regulator series, this demonstration specifically compares the input and output voltages and currents between the two different components, as well as points out some of the key operational differences. Right away, you can see that the part count of the LM78 is several components including a heat sink, thermal paste, nuts and bolts and, of course, the extra labor – while the R-78 solution’s part count is a single part number.
It’s important to understand what’s going on here and how a linear regulator actually works. A linear regulator is simply a voltage regulator, so the input current and output current are always the same. A switching regulator, on the other hand, is a power converter. So as the input voltage increases, the input current will decrease. This has the advantage of significantly reducing power losses resulting in excessive heat in the application. Our switching regulators run at efficiencies above 90% regardless of the input voltage.
Let’s have a look at what that really means in practice. If I configure the linear regulator to produce 5V out, you see that the input and output current are the same, meaning that the power loss is quite high. You can see in the thermal images that this will result in a significant amount of heat generated, reducing the lifetime of the entire application. When replacing the linear regulator with one of RECOM’s R-78 switching regulators with the same load, you can see that the input voltage is still the same, but the input current drawn is much less. This results in a greater amount of power being transferred to the load as opposed to being dissipated as heat. Taking a look at the thermal image, we can see that the solution is running much cooler.
The Total Cost of Ownership of a design has to be considered in this case. While the initial BOM of the linear regulator may be slightly cheaper than an R-78, other life-long factors play a role in overall cost. The heat dissipation that reduces the lifetime of the nearby components needs to be considered. Plus, the part count is reduced, which simplifies sourcing and BOM management. Finally, as the modules are pre-certified and EMC tested, time-to-market is greatly improved over creating a discrete solution with thermal management integrated.