Digital Power Management Bus Specification Released with Support from Special Interest Group

March 30, 2005
Revision 1.0 of the Power Management Bus (PMBus) open-standard digital power management protocol has been formally released

Revision 1.0 of the Power Management Bus (PMBus) open-standard digital power management protocol has been formally released. Simultaneously, a special interest group (SIG), known as the System Management Interface Forum Inc., has been established to further develop, enable and promote the PMBus power operating system.

The PMBus specification is structured into two parts. The first part covers general requirements, defining the transport, electrical interface and timing requirements of hardwired signals. The second part defines the command language used by the PMBus. According to Artesyn Technologies, the specification is complete and ready for immediate implementation.

Led by Artesyn Technologies and other power supply and semiconductor companies, the PMBus protocol is a collaborative venture 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 chip manufacturers Intersil, Microchip Technology, Texas Instruments, Volterra Semiconductor, Summit Microelectronics and Zilker Labs.

Since the coalition was first formed, a number of power supply and component companies have endorsed the protocol and announced their intentions to develop compliant products. Earlier this year, members of the Distributed-power Open Standards Alliance (DOSA) indicated their support for PMBus. And late last year, members of the Point-of-load Alliance (POLA) gave their support to PMBus, although in reality all the POLA members except Ericsson already were founding members of the PMBus initiative.

The establishment of the System Management Interface Forum as a formal SIG is meant to make the PMBus protocol available to a wide audience. The group established a working committee known as the PMBus Implementers Forum, which just released the first formal revision of the protocol specification at the group’s website,

Companies wishing to join the forum can download a membership application at the powerSIG website. New members that choose to become PMBus adopters will be eligible to contribute to future specifications and revisions, as well as participate in working groups for related projects. Other benefits of membership include free technical support; access to white papers, design guides and application notes; access to compatibility tests and software drivers; and five free copies of each hardcopy specification. However, two benefits are available to both forum members and nonmembers alike. These are the ability to download the specification and the ability to sign an open IP agreement.

“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. Artesyn is a longstanding advocate of open architecture systems to help customers improve time-to-market and streamline costs by adopting standard platforms. We expect the first compliant semiconductors and digital POL converters to hit the market during the summer.”

The System Management Interface Forum Inc. (also known as SMIF) is registered under the Texas Non-Profit Corporation Act and complies with Section 501(c)(6) of the Internal Revenue Code. Its business is not conducted for the financial benefit of members, but for the purposes outlined herein. In addition to the PMBus protocol, the SMIF also will assume responsibility for supporting the technologically related System Management Bus (SMBus) defined by Intel Corp. for low-speed system management communications in PCs and servers, together with the Smart Battery System Implementers Forum (SBSIF).

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