National Semiconductor’s latest high-voltage system power management and protection devices include on-chip support for the power management bus (PMBus). 

The chips are designed to supply a system management host with real-time power, voltage, current, temperature and fault data for each node in the system. 

It uses the system management bus (SMBus) communications interface implementing the PMBus protocol.  

There is a 48V input device and a -48V input device. The LM5066 features a voltage input range of 10V to 80V and the LM5064 operates over a range of -9V to -80V. 

Both ICs have selectable 25mV/50mV current limit thresholds for addressing a range of intermediate bus voltages and load currents. 

A measurement block measures both current and voltage at 1,000 times per second with 4.5% accuracy over the full temperature range. 

Additionally, simultaneous sampling of current and voltage provides true power measurement of the system’s power consumption.

The measurement block also captures the peak current and peak power and computes the average of subsystem operating parameters (Vin, Iin, Pin and Vout) over a user-programmable time frame, offloading the processing burden from an external microcontroller.