Design Win

19 V - 90 W adapter based on the STCMB1, TM PFC and HB LLC combo controller

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Product overview


The EVLCMB1-90WADP demonstration board is a 19 V - 90 W converter, tailored for the typical specification of an ac-dc adapter for laptops and notebooks, with a wide input mains range and very low power consumption under light-load.

The architecture is based on a two-stage approach: a front-end transition mode PFC pre-regulator and a downstream LLC resonant half-bridge converter; the PFC and LLC are both integrated in the STCMB1 combo IC.

The PFC section uses a proprietary constant on-time control methodology that does not require a sinusoidal input reference, thereby reducing the system cost and external component count. The LLC section is based on a proprietary time shift control method with simple compensation; this improves the dynamic behavior and input ripple rejection resulting in a cleaner output voltage bringing advantages to the circuitry placed to the SMPS secondary side.

The STCMB1 device also embeds a high voltage start up generator, an x-capacitor discharge circuit and a complete set of protections. These features are fully exploited in the EVLCMB1-90WADP device to make a robust and safe SMPS, while keeping a reduced external component count.

The EVLCMB1-90WADP device is characterized by very high efficiency at the light loads that comes from the combination of the design and selection of the power components and the innovative burst mode management functions integrated in the STCMB1, including a proprietary IP that allows minimizing the number of cycles in the burst packet and so minimizing the switching losses.

  • All features

    • Universal input mains voltage range: from 90 V ac to 264 V ac- frequency from 45 to 65 Hz
    • Output voltage: 19 V, 4.75 A continuous operation
    • Average efficiency: > 90%, according to European CoC ver. 5 Tier 2 for external power supplies
    • Efficiency > 60% with Pout = 250 mW, according to EuP lot 6 Tier 2 for household and office equipment
    • No load mains consumption: < 90 mW at 230 V ac, according to European CoC ver. 5 Tier 2 for external power supplies
    • Mains harmonics: meets EN61000-3-2 Class-D and JEITA-MITI Class-D
    • EMI: according to EN55022 Class-B
    • Safety: meets EN60950 standards
    • RoHS compliant

Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade WEEE Compliant Material Declaration**
CARD Industrial Ecopack1 -




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(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.

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