Electronic Design

The Paradigm Shift to Digital Control

Digital control isn’t an incremental improvement to analog, it’s a major paradigm shift. To be viable, digital control must represent a significant advantage in all areas of consideration. It must deliver significant performance advantages over analog plus the more tactical benefits of cost, size, and integration. Today, digital control is a new technology making its way into targeted applications where specialized functionality, increased integration, higher efficiency, faster transient response, and programmability are key.

As digital power control gets closer to price parity with analog, an increasing number of suppliers will jump into the digital fray. Ultimately, digital controllers will compete head-on with the analog solutions that are taking the higher-volume segments of the market. The rate of assimilation of digital power-supply control will be directly related to three practical considerations: cost economies of digital versus analog, the tangible benefits brought about by digital control, and the rate of digital control learning in the user community.

Cost is key in the power-supply business. The end customer generally will be reluctant to pay more for a higher-performance power delivery system unless there are significant advantages. That said, system cost is more than just the bill-of-materials. Other tangible costs, such as manufacturing labor and overhead, customer support, and warranty returns, must be included in any analog “break-even” analysis. To this end, digital power control has a long-term cost advantage over its analog control counterparts due to higher integration and the cost savings resulting from the use of commodity digital IC fabrication technology.

This leads to the next key consideration: tangible benefits brought by digital power-supply control. The power system provider must see clear advantages in adopting digital control and be able to quantify these advantages in dollars. For example, digital control’s programmability allows a power-supply hardware design to be modified in software for custom power applications, resulting in upside revenue opportunities. In essence, this enables the development cost of a single hardware design effort to be amortized over several end products, lowering average development cost and expanding market reach. Other benefits include digital diagnosis of impending system faults for greater reliability, remote configuration and diagnosis for lower customer support costs, and computer-aided manufacturing test for lower test costs.

Additionally, modern power-supply designers are analog specialists, many of whom have limited digital design skills. Comfort zones being what they are, these designers will always resort to that which they know best when implementing a power system. This behavior will likely become less common as the power-supply design community gains experience with digital control design techniques.

Taking these factors into consideration, we’re already seeing digital controllers being used primarily for performance in relatively higher-end, lower-volume applications. By utilizing easy-to-use tools, designers of these systems are quickly becoming proficient in digital control and are more aggressively leveraging this technology to its greatest advantage within the system. Given time, these advanced control techniques will trickle down into the lower-cost, higher-volume applications, and this broad-based adoption will push digital control into the mainstream.


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