Even though power management is critical to the reliable operation of modern electronic systems, voltage regulators are perhaps the last remaining “blind spot” in today’s systems, without the means for directly configuring or monitoring key power system operating parameters. As a result, power designers have been forced to use a mixed bag of sequencers, microcontrollers and voltage supervisors to program basic regulator start-up and safety functions.
Digitally programmable DC/DC converters have been available for many years, most notably in VRM core power supplies with VID output voltage control. But the ability to monitor operating status information directly from the voltage regulator, especially real-time currents, has been missing.
Use of a standard serial digital bus, such as I2C, enables simple and efficient communications to and from digitally equipped DC/DC converters, while emerging standards like PMBus facilitate component interoperability. Important regulator parameters including startup characteristics and timing; output voltages and current limits; margining specifications; and overvoltage and undervoltage supervisory limits can all be directly programmed digitally, instead of being set with resistors and space-consuming sequencing and monitoring products.
Further, critical operating parameters such as temperature and input and output voltages and currents can be routinely monitored and used to optimize system performance and reliability.
A principal benefit of digital power system management is reduced design cost and faster time to market. Complex multi-rail systems can be efficiently developed using a comprehensive development environment with intuitive graphical user interface (GUI). Such systems also simplify in-circuit testing (ICT) and board debug by enabling changes via the GUI instead of soldering in “white wire” fixes.
Another benefit is the potential to predict power system failures and enable preventive measures, thanks to the availability of real-time telemetry data. Perhaps most significantly, DC/DC converters with digital management functionality allow designers to develop “green” power systems that meet target performance (compute speed, data rate, etc.) with minimum energy usage at the point of load, board, rack and even installation levels, reducing infrastructure costs and the total cost of ownership over the life of the product.
New ICs such as Linear Technology’s LTC3880 incorporate all of these capabilities--and more. Digital power system management holds the promise of enabling higher performance with lower energy usage in next-generation "green" electronic systems.
About the author
Don Paulus is Vice President & General Manager, Power Products, Linear Technology Corporation (Milpitas, CA).