The System Management Bus (SMBus) is a two-wire communication protocol derived from I2C, designed primarily for lightweight system management communications on computer motherboards and embedded systems. While based on the I2C architecture, SMBus imposes stricter timing and electrical parameters to ensure robust operation and predictability.
Originally defined by Intel in 1995, SMBus is utilized for low-speed tasks such as monitoring smart battery status, reading temperature sensors, and controlling cooling fans. It operates on a master-slave architecture using clock (SCL) and data (SDA) lines. Due to its design focus on reliability and control rather than speed, it is optimized for command transmission rather than high-bandwidth data transfer.
In the context of power electronics, SMBus serves as the foundational physical and transport layer for the PMBus (Power Management Bus) protocol. PMBus extends SMBus by defining a standardized command set specifically for digital power management. Therefore, SMBus compatibility is a key factor when integrating modern digital power supplies and enabling system-level monitoring.