IR Increases Multi-Phase Converter Efficiency by Three Percent

International Rectifier (IR) has expanded the IR XPhase™ family of scalable multi-phase converter chipset devices with the IR3084 and IR3084U XPhase control ICs. The new control ICs are designed to be used with IR's existing IR3086A phase IC and companion DirectFET® power MOSFETs such as the IRF6617 and IRF6691 to achieve as much as three percent higher efficiency in 130A applications with seven phases, compared to competing five-phase designs.

The IR3084 supports Intel® VR10.x and VR11 microprocessor core power requirements, while the IR3084U is a universal voltage identification (VID) device for VR10.x and VR11 as well as AMD Opteron™ VID codes and start-up sequences.

The XPhase chipset is designed to increase power density and efficiency in desktops, servers, voltage regulator modules (VRM) and embedded systems. By increasing the number of phases from five to seven, the current in each phase is decreased, and enables the use of smaller inductors and reduced output capacitors. This enables a reduction in footprint size from 3200 square millimeters to 2400 square millimeters, a 25 percent reduction in board area.

The seven-phase IR3084 solution including the IRF6617 and IRF6691 power MOSFETs achieves 88 percent efficiency at full load current and eliminates the need for a heatsink.

"Removal of the regulator heatsink reduces manufacturing costs and improves airflow to the CPU in low-profile 1U and blade servers. This improves system performance and long-term product reliability," said Faisal Ahmad, marketing manager for DC-DC Computing Products at International Rectifier.

Both control ICs include 0.5 percent overall system accuracy and differential remote voltage sensing. The ICs offer a programmable 150kHz to 1MHz oscillator, remote temperature sensing, and loss-less DCR current sensing with programmable hiccup over-current protection. The IR3084U includes a VID select pin which allows for simple migration from AMD to Intel VID codes.