Smart power stages feature integrated current monitors

2nd December 2016

Vishay

Alice Matthews

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Datasheet

Meeting the need for real-time processor and memory power consumption monitoring in telecom equipment and datacentre servers, Vishay Intertechnology has introduced two 60A VRPower smart power stages with integrated current and temperature monitors for multi-phase DC/DC systems.

Combining power MOSFETs, an advanced driver IC, and a bootstrap FET in the thermally enhanced low-profile 5x5x0.66mm PowerPAK MLP55-32L/QFN package, the Vishay Siliconix SiC645 and SiC645A simplify designs and deliver higher accuracy than comparable standard DrMOS products while offering a 16% smaller footprint than similar competing devices, according to the company.

Unlike solutions that monitor power consumption using inductor DCR sensing — a technique with lower accuracy that requires external components such as a thermistor for temperature compensation — the SiC645 and SiC645A utilise low-side MOSFET RDS(ON) sensing to accurately report current (IMON) and temperature (TMON) using 5mV/A and 8mV/C signals, respectively. This method of current sensing is accurate over a wide load range and is internally temperature-compensated, simplifying designs by removing the need for external circuitry. In addition, it eliminates current sense traces while delivering fast performance without noise or external filtering.

The power stages' improved accuracy meets Intel's stringent VR13 and VR13.x current monitoring accuracy requirements and allows for better utilisation of a server CPU's turbo boost capability, a critical advantage for datacentre customers requiring improved performance without increasing costs. Light-load efficiency is supported by a dedicated low-side FET control pin.

The devices offer an input range of 4.5-18V and are optimised for high-frequency and high-efficiency VRMs and VRDs to power microprocessors and memory for servers, networking, and cloud computing; GPUs in graphic cards and video game consoles; as well as general purpose multi-phase Point-Of-Load (POL) DC/DC converters. The package of the SiC645 and SiC645A can be cooled on both sides, while low package parasitic resistance and inductance enable high switching frequencies of up to 2MHz.

Fault protection features for the RoHS-compliant, halogen-free devices include high-side FET short and overcurrent protection, over-temperature protection, and Undervoltage Lockout (UVLO). The power stages feature open drain fault reporting output. The SiC645 and SiC645A support 5 and 3.3V PWM tri-level input, respectively, and are compatible with Intersil's ISL68/69xx and ISL958xx digital multiphase controllers.