EDN's 18th Annual Innovation Awards Finalists

EDN Staff - February 1, 2008

&& PREVIOUS FINALIST | MAIN | NEXT FINALIST >>

Category: Power Sources
Finalist: CAR2500 front end/rectifiers (Cherokee)

Today’s data centers face two primary constraints: power efficiency over a wide load range, and rack real estate. The CAR2500 series of front-end rectifiers optimizes efficiencies, reduces losses, and provides maximum power in a compact package. The CAR2500 series minimizes switching and conduction losses with a power-factor-correction stage, resulting in 97% efficiency for this stage. The rectifier stage uses a ZVS (zero-voltage-switch) full-bridge design; low-on-resistance MOSFET to minimize conduction losses; a proprietary clamp circuit to recycle 40% of the energy normally lost as heat, netting an additional 2% gain in efficiency; and an output frequency of 400 kHz to minimize core and copper loss and size. The optimized drive circuit with synchronization further minimizes switching losses. The system’s transformer has a current-doubler circuit on multiple secondaries to provide equal energy transfer and to balance thermal losses, which also lowers heat. As an example, the CAR2548TN member of the series is a 1U, —54V rectifier targets telecom applications. Four of the 27W/in.³ units fit side by side in a 1U power shelf for as much as 10,000W or 7500W N+1 redundant power. Similarly, the CAR2512FP 1U 12V front-end unit operates at 88% power efficiency at 25% load and 91% efficiency at 50% load.