When designing industrial PCs, one question that puzzles system engineers is how to improve system efficiency. PC applications use a complex quad core or octa-core processor like the Sitara™ AM57x or Intel’s Apollo Lake or Braswell processor. The power for these processors runs off a 5V bus supply. Most systems use a multistage architecture to drive power from 19V, or a 12V adapter to a 5V bus. In this type of architecture, the power is lost at two levels: across 19V stepping down to 5V and then 5V stepping down to 1V. Architecturally, the peak efficiency of the first stage and second stage is 92%, which results in a best-case system efficiency of 84.6% (92% × 92%) at the processor.

It’s not surprising why there’s a multistage architecture, because most power management IC (PMICs) available today operate only up to 5.5V. One simple way to improve efficiency is to implement the power architecture in such a way that eliminates the need for a multistage power source, leaving the option to use a 12V or 19V power input to the PMIC. This architecture eliminates extra power loss in the first stage.

With the introduction of the TPS65086, a configurable multi-rail PMIC for 2S and 3S Li-ion battery-operated devices, you can make power design very simple and improve overall system efficiency. The device eliminates the need for a multistage power architecture, taking direct 12V inputs from the bus to step down the voltage using integrated DC/DC converters to power the processors. The TPS65086 eliminates the need for an extra LDO for DDR termination with a built-in VTT LDO that can support up to 16GB of memory. This makes the overall system very simple and easy to implement, as shown in Figure 1.


 Figure 1: AM57x single-stage power scheme

The TPS65086 PMIC also allows you to change the memory on the system by allowing the memory voltages (which can be also pre-programmed in the device) using as in built one time memory and a control pin on the device.

By eliminating a multistage power architecture, you not only improve the system efficiency but also save system cost.

Additional resources