UCC2913

UCC2913 UCC3913 SLUS274A – JANUARY 1999 – REVISED APRIL 2003 NEGATIVE VOLTAGE HOT SWAP POWER MANAGER FEATURES DESCRIPTION D Precision Fault Threshold D Programmable Average Power Limiting D Programmable Linear Current Control D Programmable Overcurrent Limit D Programmable Fault Time D Fault Output Indicator D Shutdown Control D Undervoltage Lockout D 8-Pin SOIC APPLICATIONS D –48-V Distributed Power Systems D Central Office Switching D Wireless Base Stations SIMPLIFIED APPLICATION DIAGRAM R1 3 RVDD Power Limiting RPL 8 DC/DC Converter or Load The UCCx913 family of negative voltage circuit breakers provides complete power management, hot-swap, and fault handling capability. The device is referenced to the negative input voltage and is driven through an external resistor connected to ground, which is essentially a current drive as opposed to the traditional voltage drive. The on-board 10-V shunt regulator protects the device from excess voltage and serves as a reference for programming the maximum allowable output sourcing current during a fault. In the event of a constant fault, the internal timer limits the on-time from less than 0.1% to a maximum of 3%. The duty cycle modulates depending on the current into the PL pin, which is a function of the voltage across the FET, and limits average power dissipation in the FET. The fault level is fixed at 50 mV across the current-sense resistor to minimize total dropout. The fault current level is set with an external curren...