Three-phase PWM control IC has integrated drivers for desktop computers

El Segundo, CA, November 2004 — International Rectifier, IR, a global provider of power management technology, introduces the IR3093, a three-phase interleaved pulse width modulation (PWM) control IC that supports several microprocessor families: AMD Athlon, AMD Opteron, AMD Athlon64 and Intel VR10.X processors. Typical applications include desktop computer motherboards, voltage regulator modules (VRM), video graphics cards and telecom single in-line (SIP) modules.

The IR3093 is suitable for space-constrained systems requiring greater than 60A of load current. In comparison to competitive devices that require external gate driver ICs, the IR3093 integrates MOSFET drivers, reducing part count by 75%. The end result is simplified circuit design, improved system reliability and reduced solution size. Together with IR's DirectFET technology MOSFETs, circuit designers can realize an efficient, space-saving solution.

“For the Performance Desktop platform which requires 101A thermal design current, the IR3093 meets the challenge of providing processor power in smaller form-factors such as BTX with only a single pair of IRF6623 and IRF6620 DirectFET MOSFETs per phase,” said Ralph Monteiro, Marketing Manager for DC-DC Computing Products.

The term BTX (balanced technology extended) refers to a personal computer form factor specification created to standardize size, performance, features and cost.

Technical Highlights
The IR3093 operates from a single 12V supply and includes a linear regulator to power the gate drivers. The regulator output voltage can be programmed to minimize switching losses and optimize efficiency. A programmable oscillator, with a frequency range of 100kHz to 540kHz, gives the designer additional flexibility to improve system efficiency and transient response.

For system protection and reliability, the IR3093 features programmable soft-start and hiccup over-current protection. Current sensing is achieved with loss-less inductor current sensing which improves accuracy compared to sensing circuits measuring MOSFET on-resistance. Dual under-voltage lockout circuits and over-voltage protection ensure reliability of system voltages. A power-good output signal indicates proper operation.

To meet the stringent power requirements of today's microprocessors, the output voltage can be programmed with either a five- or six-bit voltage identification (VID) code with 0.5% set-point accuracy. An adaptive voltage-positioning feature maintains the output voltage tolerance while minimizing output capacitor requirements. A patent-pending body braking circuit reduces the output capacitance requirement by an additional 25% further reducing system costs.

Following the trend of increasing power requirements in microprocessors, the IR3093 is pin-compatible with the two-phase IR3092, giving designers the flexibility to migrate from a two-phase design to a three-phase solution with a single PCB layout. This feature can save significant development time as designs incorporate more advanced microprocessors.

IR3093 data sheet

The IR3093M PWM IC is available immediately in the MLPQ-48, 7 x 7 package. Pricing is US $3.10 each in 10,000-unit quantities.

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