Digital power management bus protocol specification released

April 26, 2005


rtesyn Technologies has announced the public release of Revision 1.0 of the PMBus open-standard digital power management protocol and the formal establishment of a special interest group (SIG) known as the System Management Interface Forum, charged with further developing, enabling and promoting the Power Management Bus (PMBus) power operating system.

Pioneered by Artesyn and other power supply and semiconductor companies, the PMBus protocol initiative is a collaborative venture by the industry to establish the first truly open communications standard for the digital control of power systems. In addition to Artesyn and Astec Power, a division of Emerson Network Power, the initial coalition comprised leading semiconductor manufacturers Intersil, Microchip Technology, Texas Instruments, Volterra Semiconductor, Summit Microelectronics, and Zilker Labs. Since the coalition was first formed, most major power companies have endorsed the protocol and announced that they intend developing compliant standard products.

The establishment of the System Management Interface Forum as a formal SIG is a significant advancement in making the PMBus protocol available to a wide audience. The group set up a working committee known as the PMBus Implementers Forum, which has just released the first formal revision of the protocol specification available at the group’s official web site: A downloadable membership application form is also available on the website for new companies wishing to join. Members can contribute to future specifications and revisions, and participate in working groups for related projects, if they choose to become PMBus adopters.

“We are extremely pleased that the PMBus initiative now has a formal organization to support and accelerate continued PMBus development,” said Todd Hendrix, VP Worldwide Marketing & Business Development with Artesyn and member of the board of directors for the newly minted SIG. “This will accelerate the adoption of a standard protocol across a wide industry base, to the benefit of all OEM system designers, power supply and semiconductor manufacturers alike. We expect the first compliant semiconductors and
digital POL converters to hit the market during the summer.”

According to Dave Heacock, co-chairman of the System Management Interface Forum and vice president for Portable Power Management at Texas Instruments, “The PMBus protocol,
implemented over the industry-standard SMBus serial interface, offers system developers an ideal route for digital control of power products in the near future.”

The PMBus digital protocol establishes an open, industry standard communication format to support these future products and addresses the desire of OEM customers to have open standards that result in multi-sourced products. OEM customers can continue to design their systems’ power architectures using discrete components or turnkey converter solutions. However, once the new protocol is widely adopted, the OEM reportedly will be able to control all compliant converters using the same set of commands.