Adding digital controls to power supplies might not be entirely new, but a variety of market drivers combine to stimulate adoption across a surprising range of industry segments.
Digital control in power supplies is a broad field, ranging from basic digital signaling (such as on/off) to a traditional analog controller to more sophisticated operations, including a digital signal processor (DSP). While the latter represents an additional cost, rapidly declining chip price points and increasingly sophisticated demand from manufacturers means that adoption is rocketing.
There are clear benefits to fully digital power supplies, mainly due to their vastly improved flexibility. The possibility of adjusting power supply performance characteristics based on different applications, and indeed environmental factors and system performance variables, opens up a vast field of practical benefits and, not least, cost savings.
Because the latest microcontrollers with DSP can sample output voltage every switching cycle, monitoring fault and status conditions, responding to warnings, and event logging are all practical options that would previously require hardware changes. In a world of increasing IIoT device demand and deployment, often in applications where physical access is prohibitively challenging, this flexibility is powerful. In addition, the location of many such devices on the network edge makes the value of real-time monitoring at this level beneficial for a host of reasons, not least predictive maintenance and improving efficiency.
Smart factory or Industry 4.0 manufacturing applications are particularly appropriate for digitally controlled power supplies. The detailed logging can be integrated with other data in AI tools or dashboards to ensure that performance parameters are managed in real-time. A hidden benefit is the ‘data lake’ of historical performance data that can be extracted from these logs, enabling predictive and preventative maintenance modeling to be enormously enhanced.
That digitally programmable ability becomes particularly essential in ruggedized components and their intended operating environment, offering increased product lifetime and enhanced energy consumption. Optimizing energy consumption by mapping and matching the power supply performance to the system power budget is of particular value in more extreme conditions, where thermal variations may impact standard performance. As a result of this, it is not only IIoT enterprises that are actively taking an interest in digital power supplies. According to recent analyst reports, global military requirements are accelerating rapidly, driven specifically by the improvements offered by digital power management.
One report from Transparency Market Research predicts that the global next-generation military power supply market is expected to reach a value of US$ 20,111.7m by 2026, expanding at a CAGR of 5.2% during that forecast period (2018 to 2026). According to TMR analysis, the programmable power supply segment holds the maximum market share and is estimated to expand at a CAGR of 5.5% through 2026. Although there are many military applications for programmable power supplies, one key overall driver is to protect militarily significant sensitive electronic devices from grid power quality instability – whether that instability is caused by everyday environmental factors or malicious actors.
Another key growth market for digitally programmable and ruggedized power supplies is, of course, the telecommunications industry, which needs robust and rugged power supplies that can be installed in telecommunication towers. Those towers face a variety of challenges, from high-salt marine environments near the coast to very dusty city locations and everything in between. Keeping maintenance costs to a minimum is crucial to controlling margins, especially when considering the new costs of 5G network upgrades.
While there is a vast range of applications and environments that can benefit from a digital power management solution, narrowing the field down for a specific application is critical. Although the headline benefits of digital power management, such as reduced cost and number of components, improved development time envelopes, and an increased number of DC-DC converter options, attract plenty of attention, there are design challenges here.
Key considerations include general power supply design requirements such as reducing undesirable ripple, and managing direct current resistance (DCR), as well as specific digital power management challenges, most crucially control algorithms, and firmware design. Indeed, these have been responsible for many delayed digital power management implementations. The control algorithm, in particular, is of central importance. Although it can be optimized and updated ‘down the track,’ it’s vital that sufficient expertise is brought to bear at an early stage in the design process.
One of those central design challenges is stability, which has traditionally forced analog systems into a series of costly compensation techniques. Digital power management systems can solve this conundrum, offering compensation-free power converters with high bandwidth and improved transient response. This is achieved by creating an entirely synthetic current control loop that provides cycle-by-cycle phase current balancing. This is particularly crucial for complex multiphase power supplies for large CPU, FPGA, or ASIC arrays widely used in rendering and artificial intelligence (AI) operations.
A key benefit of digital power management is that it is possible to control and monitor every setting via software, making designing and tuning loops a simpler process. Still, the hidden benefit is in debug time, as the status and condition of the power supply are immediately clear. The subsequent ability to adjust filters and compensate for noisy conditions in software and near-real-time adds flexibility to solving any specific challenges that emerge and speed the process.
Finally, because the power supply should be operating at an optimum level, thermal performance should be excellent, in many cases enabling cooling provisions such as airflow and heat sinks to be optimized or even omitted. This contributes to a slimline design that can fit into restricted spaces and cabinets much more readily.
It’s not hard to see why digital control of power supplies is gaining momentum across the board. From improving flexibility and lowering operating costs to extending lifespan in rugged and difficult to access locations and integrating with wider IIoT strategies such as predictive maintenance and modeling, there is an extensive list of benefits. Although analog control still has a role to play in simple and low-power applications, the rising revolution will indeed be digitized.