The UCC39002 is an advanced, high performance and low cost loadshare controller that provides all necessary functions to parallel multiple independent power supplies or dc-to-dc modules. Targeted for high reliability applications in server, workstation, telecom and other distributed power systems, the controller is suitable for N+1 redundant systems or high current applications where off-the-shelf power supplies need to be paralleled.

The BiCMOS UCC39002 is based on the automatic master/slave architecture of the UC3902 and UC3907 load share controllers. It provides better than 1% current share error between modules at full load by using a very low offset post-package-trimmed current-sense amplifier and a high-gain negative feedback loop. And with the amplifier’s common mode range of 0-V to the supply rail, the current sense resistor, RSHUNT, can be placed in either the GND return path or in the positive output rail of the power supply.

The functionality of the UCC29002/1 differs slightly compared to the UCC39002. The UCC39002 will force the maximum adjustment range at start up to quickly engage load sharing; the UCC29002/1 ADJ amplifier will operate in a linear mode during start up, resulting in a more gradual load sharing at turn on.

During transient conditions while adding or removing power supplies, the UCC39002 protects the system by keeping the load share bus disconnected from the remaining supplies. By disabling the adjust function in case a short of the load share bus occurs to either GND or the supply rail, it also provides protection for the system against erroneous output voltage adjustment.

The UCC39002 also meets Intel’s SSI (Server System Infrastructure) loadshare specifications of a single-line load share bus and scalable load share voltage for any level of output currents.

The UCC39002 family is offered in 8-pin MSOP (DGK), SOIC (D), and PDIP (P) packages.

• High Accuracy, Better Than 1% CurrentShare Error at Full Load
• High-Side or Low-Side (GND Reference) Current-Sense Capability
• Ultra-Low Offset Current Sense Amplifier
• Single Wire Load Share Bus
• Full Scale Adjustability
• Intel® SSI LoadShare Specification Compliant
• Disconnect from Load Share Bus at Stand-By
• Load Share Bus Protection Against Shorts to GND or to the Supply Rail
• 8-Pin MSOP Package Minimizes Space
• Lead-Free Assembly
• SYSTEM CONFIGURATIONS
  • Modules With Remote Sense Capability
  • Modules With Adjust Input
  • Modules With Both Remote Sense and Adjust Input
  • In Conjunction With the Internal Feedback E/A of OEM Power Supply Units