IR Intros XPhase Architecture for DC Converters

International Rectifier Corp. (IR, El Segundo, CA) introduced its new XPhase, a flexible and scalable architecture for multi-phase, interleaved, buck dc/dc converters requiring one or more phases. The first XPhase chip set consists of the IR3081 control IC and the IR3086 phase IC, which provides a high-performance solution that exceeds the VRM or VRD/EVRD 10.0 requirements for the most advanced microprocessors used in servers and high-end desktop computers.

The XPhase architecture consists of a control IC, which communicates with the phase IC using a simple five-wire bus scheme. Phases can be added or removed without changing the fundamental design. The five-wire analog bus consists of bias voltage, phase timing, average current, error amplifier output and VID voltage. By eliminating point-to-point wiring between the control and the phase ICs, the five-wire bus shortens interconnections, cutting parasitic inductance and noise and improving PCB layout.

The IR3081 control IC in the 28-lead, MLPQ package contains all one-per-converter circuitry, including voltage identification pull-up resistors, a pulse-width modulation ramp oscillator, an error amplifier, bias voltage, fault detection and other necessary functions. The IR3086 phase IC in the 20-lead, MLPQ package drives and monitors a single phase in a multi-phase converter. The IR3086 phase IC includes all one-per-phase circuitry that includes gate drivers, a pulse-width modulation comparator and latch, over-voltage protection, current sensing and sharing, and programmable VRHOT over temperature detection.

The IR3081 controller IC is priced at $1.65 each. The IR3086 phase IC is priced at $1.25 each.