Energy monitoring hot swap controller enables 100A+ boards

High current hot-pluggable boards utilise parallel MOSFETs to reduce voltage drop, but all of these MOSFETs require large Safe Operating Areas (SOA) to ride through overcurrent faults. By controlling two matching current limited paths, the LTC4282 halves each path’s SOA requirements, reducing MOSFET costs in high current applications (over 50A).

Further cost savings are afforded with a staged start configuration employing a low SOA MOSFET in one path and low RDS_(ON) MOSFETs in the other path. The LTC4282 provides a rugged, compact solution for hot plugging and monitoring, especially in high power circuit boards in servers, network routers and switches, and enterprise data storage systems.

Sitting at the gateway to board power, the LTC4282’s ±0.7% accurate ADC reports board voltage, current, power and energy consumption through an I²C/SMBus digital interface. During overcurrent conditions, the LTC4282 folds back its 2% accurate current limit to maintain constant MOSFET power dissipation for an adjustable timeout period.

Digitally configurable current limit enables dynamic adjustment with load changes and eases selection of low value sense resistors. Minimum and maximum values of the monitored electrical parameters are recorded, with alerts raised when they exceed 8-bit thresholds. Internal EEPROM provides nonvolatile storage for register configuration and fault log data. To prevent catastrophic damage to the board, the MOSFETs are continuously monitored for abnormal conditions such as low gate voltage and drain-to-source short-circuit or large voltage drop.

Specified over the 0 to +70°C commercial and -40 to +85°C industrial temperature ranges, the LTC4282 is offered in a 32-pin 5mm² QFN package. 1,000-piece pricing starts at $5.95 each. Device samples and evaluation circuit boards are available online or from your local Linear Technology sales office.