PowerSource

Digital power control ICs for dc-dc power supplies fall into two broad categories*: Those that use a programmable DSP to perform the voltage control loop algorithms, and those , that use a state machine in combination with some analog functions in a mixed signal implementation: The state machine algorithms are relatively fixed, compared to the completely programmable DSP approach. Irish start-up Powervation has launched what CEO Antoin Russell calls “a new class of power converter”.

Powervation’s platform combines the analog, the DSP, and the RISC processor into a mixed-signal SOC that makes use of the company’s set of proprietary control algorithms the company calls “Auto-control.” Auto-control performs a cycle by cycle optimization of the control loop and takes into consideration all the variations of the power train, from component variations to instantaneous load changes, and automatically adjusts the loop compensation to guarantee stability and position it at the most efficient operating point. All of the system parameters are massaged and refined in a single parameter the company calls “MOJO” which allows a single adjustment for performance and stability.

Rather than try to fit all of the control loop functions as well as the communication tasks into one processor, Powervation went with two separate, proprietary processors. Russell said, “One of the biggest issues you’ve got [in digital control loop programming] is partitioning the functions of the DSP between synchronous and asynchronous activity. The control of the voltage loop is a synchronous activity that you really can’t interrupt, while serial communications, for example, is effectively asynchronous. Trying to balance an implementation in a single DSP core for multiple processes is practically impossible to do in software.” In addition, using their own proprietary processors allowed Powervation to both shrink the size of the processors within the SOC as well as save power.

The company is claiming system efficiency gains of up to 30% with a 50% improvement in transient response. In addition to the usual target markets for digital power of PC/server and telcom power supplies, the company is also aiming the chip at the consumer space, including HDTVs and set-top boxes, indicating a fairly low price point, although Powervation isn’t talking price at this time other than saying it will meet or beat the price of digital control chips with equivalent specs. We’ll find out more at Digital Power Forum in San Francisco next week, when the company formally introduces the platform.

*(There’s also a third approach which has an analog control loop with a digital wrapper around it to support digital housekeeping and communication functions.)