The Power Management Bus (PMBus) is an open-standard digital communication protocol designed specifically for configuring, monitoring, and controlling power conversion devices. It is built on the physical layer of the System Management Bus (SMBus), a derivative of the I2C protocol. PMBus defines a standardized command language, ensuring interoperability between power supplies and devices from different manufacturers.
A host controller, such as a main processor or microcontroller, uses PMBus to manage multiple power supplies within a system. This protocol allows precise configuration of output voltages and currents, as well as protection limits like over-voltage and over-current trip points. Additionally, it enables real-time telemetry, allowing the host to read back actual output values, monitor internal temperatures, and detect fault warnings.
This digital control capability supports intelligent power management and improves system reliability through early fault detection. PMBus is widely adopted in complex applications requiring multiple power rails, including servers, networking equipment, and high-end industrial systems.