World’s highest light load efficiency MOSFET gate drivers save cost and board space in multiphase switching regulator designs for Intel® VR11.1 CPUs

The ISL6622, ISL6622A, and ISL6622B provide 3A sinking capacity and feature rapid rise/fall times that support up to 1MHz frequency switching. This delivers very high overall efficiency.

Combined with Intersil’s VR11.1 PWM controllers and with N-Channel MOSFETs, the ISL6622’s advanced PWM protocol supplies a complete core-voltage regulator solution for advanced microprocessors.

The ISL6622 enables diode emulation operation during PSI mode for enhanced light load efficiency and allows Discontinuous Conduction Mode (DCM) by detecting when the inductor current reaches zero. When “zero” is detected, the low side MOSFET is turned off to prevent sinking current and eliminating the power loss associated with the reverse currents. Intersil’s gate voltage optimization technology (GVOT) is also active during PSI mode; by reducing the gate drive voltage, switching losses, which dominate total power loss at light loads, are significantly reduced. This adds to the overall efficiency the ISL6622 provides.

These PWM controllers also include adaptive shoot-through protection to prevent both the upper and lower MOSFETs from conducting simultaneously. In addition, they integrate a 20 kilohms high-side gate-to-source resistor to prevent self turn-on due to high input bus differential voltage.

Overvoltage protection can be operational while VCC is below the POR threshold: the PHASE node is connected to the gate of the low side MOSFET (LGATE) via a 10 kilohms resistor, so the output voltage of the converter is maintained close to the gate threshold of the low side MOSFET. This capability protects the load in case the upper MOSFET(s) become shorted.

The drivers come in two package types with different drive voltages. In the 8-lead SOIC package, the ISL6622 drives the upper and lower gates to VCC during normal PWM mode; the lower gate drops to a fixed typical 5.75V in PSI mode. In the 10-Lead DFN ISL6222A, the upper gate can be driven from 5V to 12V via the UVCC pin; the lower gate has a resistor-selectable drive voltage of typical 5.75V, 6.75V, and 7.75V in PSI mode.

These drivers are designed for a wide range of server, workstation, desktop and gaming motherboard applications built around Intel processors. They also are an ideal design choice for VRM applications.

For more information, or details on the full range of Intersil products available from Anglia, please call +44 (0)1945 474747 or email info@anglia.com

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