EVL101G50FLT HPF Flyback Controller

Introduction

The STMicroelectronics EVL101G50FLT is a 50 W evaluation board for single-stage, high-power-factor quasi-resonant flyback conversion. It is intended as an LED-driver or AC-to-DC power-supply reference design, combining isolated secondary-side constant-voltage and constant-current regulation in a compact board.

The design is based on the HVLED101 and SEA05LTR current-mode controllers, with a sensor-less GaN transistor and planar transformer. Its combination of wide-range AC input support, high reported power factor, and quasi-resonant flyback operation makes it a useful platform for examining efficient isolated power conversion without a heatsink.

What it does

The EVL101G50FLT converts a 90 VRMS to 265 VRMS AC input at 45 Hz to 66 Hz into a regulated output. It is rated for 50 W operation and provides a 50 V output when output current is below 1 A.

For LED-oriented operation, the board supports 1 A output current with LED voltages between 20 V and 48 V. Both constant-current and constant-voltage regulation modes are provided, with isolated regulation on the secondary side.

At full load, the stated power factor is greater than 0.99 and total harmonic distortion is below 5%. The board also specifies a power factor above 0.99 at one-third load from a 230 VAC input, with THD below 7% under that condition. Average efficiency is specified above 91% across four measurement points, while standby efficiency is stated above 50% at a 240 mW output.

Applications

Potential uses that follow directly from the board’s electrical characteristics include:

• Evaluation of isolated, high-power-factor AC-to-DC flyback designs.
• Development and testing of constant-current LED power stages for 20 V to 48 V LED loads.
• 50 V constant-voltage power-supply prototyping at output currents below 1 A.
• Investigation of quasi-resonant flyback control using a GaN switching device.
• Design validation for equipment intended to operate from wide-range 90 VRMS to 265 VRMS AC mains inputs.

Design considerations

The board is a dual-layer PCB measuring 5 cm × 10 cm × 1.8 cm and is specified without a heatsink. Thermal performance, enclosure airflow, spacing, and installation conditions should therefore be considered when adapting the reference design or integrating it into a larger system.

Its input range spans 90 VRMS to 265 VRMS, while the defined input frequency range is 45 Hz to 66 Hz. Output requirements should also be matched to the stated operating conditions: 50 V operation applies below 1 A, and the 1 A LED-current specification is associated with LED voltages from 20 V to 48 V.

Because the design provides isolated secondary-side regulation and supports both constant-voltage and constant-current modes, the selected output load and intended regulation behavior should be established early in the integration process.

Availability and further information

The source/distributor and datasheet links on this page provide further information on the EVL101G50FLT, including the board documentation and purchasing reference.