power management bus (PMBus)

The power management bus(PMBus) is used for communication between the components of the power supply; between voltage regulators, power management( PM) and system controller. This communication is standardized across power supplies in the PMBus and offers particular advantages for distributed power supplies.

The PMBus mimics the control and monitoring functions already defined in the Smart Battery System( SBS), but as an open standard it provides the command and data formats for data transport. These include the alarm, the timeout of 35 ms and the error control for the data packets, the Packet Error Check( PEC). In addition, the specifications of the SMBus have been adopted in the PMBus.

The PMBus is similar in concept to the System Management Bus (SMBus) and consists of two communication lines and three signal lines for control and monitoring signals. The communication lines are used to transmit the clock signal and the data, and three signal lines are used to indicate errors and switch off voltages.

PMBus standardization is driven by the System Management Interface Forum (SMIF), an association of the SBS and PMBus consortia.