PMBus Power-Management/Protection ICs Handle High-Voltage Systems

PMBus Power-Management/Protection ICs Handle High-Voltage Systems

Fürstenfeldbruck, Germany: Two new high-voltage system power-management and protection ICs from National Semiconductor offer on-chip PMBus support.  The 48V LM5066 and -48V LM5064 integrate system protection and management blocks that measure, control, and manage the electrical operating conditions in routers, switches, and basestations. 

Both of these new ICs provide complete subsystem power management for high-voltage systems. They precisely measure the power to each card or block while continuously protecting against damaging inrush current surges caused by hot-swap or transient events that damage downstream components. 

The 5066 and 5064 employ the company’s hot-swap architecture, which monitors and limits both system current and power while accurately measuring power consumption and fault conditions. The devices continuously supply the system-management host with real-time power, voltage, current, temperature, and fault data for each node in the system. This task is handled by the system-management bus (SMBus) via the PMBus protocol.  The host’s system diagnostic and optimisation routines use the data to boost system reliability and minimise overall power consumption.

The 5066 features an input range of 10V to 80V, while the 5064 operates over a -9V to -80V range.  Each IC has selectable 25mV/50mV current-limit thresholds to address a wide range of intermediate bus voltages and load currents. A measurement block measures both current and voltage at 1000 times per second with 4.5% accuracy over the full temperature range.

In addition, simultaneous sampling of current and voltage provides true 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. As a result, an external microcontroller needn’t handle processing.

A temperature-monitoring block interfaces with a low-cost external diode to measure temperature of the external MOSFET or other critical temperature source.  The LM5066 and LM5064 report the status of all system parameters and fault conditions through the SMBus interface, offering individually programmable warning thresholds for all faults.

National Semiconductor Corp.

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