Design Win

300W High AC Input Voltage LED Driver with digital power control

Solution Description

High voltage lighting applications typically require robust and highly efficient power supplies,

able to generate tightly regulated output currents and voltages with high power factor, low THD and minimal voltage ripple.

The SL-LLL009V1 solution supports very high input voltage and achieves very high efficiency thanks to the implemented architecture, featuring a PFC stage and a DC-DC half-bridge LCC resonant converter with the secondary side synchronous rectification.

  • The Digital control stage performed by STM32F334 microcontroller guarantees high resolution timer for a fine control loop regulation. It implements digital DC-DC and output synchronous rectification control.
  • The PFC stage is based on the STW20N95K5 MDmesh™ K5 N-channel Power MOSFET driven by the L6562AT controller.
  • The Half bridge LLC converter primary section is based on the STW20N95DK5 MDmesh™ DK5 N-channel Power MOSFET for high efficiency performances. Both STW20N95K5 and STW20N95DK5 allow to handle very high AC input voltages.
  • A full bridge synchronous rectification (SR) is performed by STP100N10F7 STripFET™ F7 N-channel Power MOSFET (driven by the L6491 gate driver) reducing conduction losses.
  • In addition, thanks to the uncommon LCC configuration, this solution allows both Voltage Control and Current Control mode of Operation.

Thanks to the STGAP2D half-bridge gate driver, primary side gate driving channels are isolated from the secondary side low voltage control circuit.

Both primary and secondary sections are supplied by a flyback circuit based on VIPer26K high voltage converter for ultra-wide inputs, which provides regulated voltages to the control board, the gate driver ICs and the signal conditioning circuits.

The solution evaluation kit includes a complete FW application example.

Formal testing and measurement results confirm the ability and performance of this solution, combined with comprehensive digital control, to deliver high efficiency, power factor close to unity, and low THD across wide input voltage and load conditions.

  • Key Product Benefits

    STM32F334 - dedicated microcontroller

    The STM32F3x4 product line specifically addresses digital power conversion applications, including D-SMPS. It features an Arm® Cortex®-M4 32-bit core operating at up to 72 MHz frequency, a floating-point unit (FPU), a high-resolution timer capable of 217ps resolution, self-compensated versus power supply and temperature drift, high-speed ADCs for precise and accurate control, and an assortment of analog interfaces for protection and signal conditioning.

    STGAP2D - Gate driver

    The STGAP2D is a half-bridge gate driver which isolates the gate driving channels from the low voltage control and interface circuitry. The gate driver is characterized by 4 A capability and rail-to-rail outputs, making the device also suitable for high power applications.

    L6491 - Half-Bridge Gate Driver

    The L6491 is a high voltage device manufactured with the BCD6 “OFF-LINE” technology. It is a single-chip half-bridge gate driver for N-channel power MOSFETs or IGBTs. The high-side (floating) section is designed to withstand a voltage rail up to 600 V. The logic inputs are CMOS/TTL compatible down to 3.3 V for easy microcontroller/DSP interfacing. An integrated comparator is available for fast protection against overcurrent, overtemperature, etc

    VIPER26K - Voltage Conveter

    The device is a high voltage converter smartly integrating a 1050 V avalanche-rugged power section, with a PWM current mode control. The 1050 V-BV power MOSFET allows to extend input voltage range and reduce the size of the DRAIN snubber circuit. This IC meets the most stringent energy-saving standards as it has very low consumption and operates in burst mode under light load

    STW20N95DK5 - high voltage Power MOSFET

    These very high voltage N-channel Power MOSFETs are part of the MDmesh™ DK5 fast recovery diode series. The MDmesh™ DK5 combines very low recovery charge (Qrr) and recovery time (trr) with an excellent improvement in RDS (on) * area and one of the most effective switching behaviors, ideal for half bridge and full bridge converters

    STW20N90K5 - high efficiency Power MOSFET

    This very high voltage N-channel Power MOSFET is designed using MDmesh™ K5 technology based on an innovative proprietary vertical structure. The result is a dramatic reduction in on-resistance and ultra-low gate charge for applications requiring superior power density and high efficiency

    STP100N10F7 - fast N-Chanel MOSFET

    These N-channel Power MOSFETs utilize STripFET™ F7 technology with an enhanced trench gate structure that results in very low on-state resistance, while also reducing internal capacitance and gate charge for faster and more efficient switching

  • All Features

    •  Ability to handle very high AC voltage inputs (270-480V)
    • 300W power output on 48V DC
    • Able to support both Constant Voltage (CV) and Constant Current (CC) Mode of Operation thanks to the LCC configuration
      • in CV mode 6,25 A is the maximum current deliverable
      • in CC mode it delivers 6.25A in a voltage range of 36-48V
    • PFC working in Transition Mode simplifies front-end power stage design
    • High Power factor Correction value at full load: > 0.95%
    • Low Total Harmonic Distortion at full load: <10%
    • Digital control provides more flexibility for flickers free operation in stadium lighting application (I.E. frequency and voltage mixed control)
    • Galvanic Isolation between the gate driving channels and low voltage control and interface circuitry ensures design robustness