ST EVL400W-EUPL7 board, L4984D·L6699
Maximizing energy efficiency in multiple drive modes
Low no-load power consumption, so no SMPS is needed.


On the 7th, STMicroelectronics released the 'EVL400W-EUPL7' evaluation board, which meets the most stringent eco-friendly design standards currently available and is ready for immediate use in 400W power supply solutions.

The EVL400W-EUPL7 evaluation board maximizes energy efficiency in multiple drive modes by utilizing the capabilities of ST's current-mode PFC controller L4984D and resonant half-bridge controller L6699.

The maximum load efficiency is 93% at 230VAC and 91% at 110VAC, and the power consumption in a no-load state is less than 0.150W, meeting the ENERGY STAR® version 6.1 for computers, as well as the European EuP Lot 6 Tier 2 requirements for home and office equipment and the Code of Conduct (CoC) version 5 Tier 2 requirements for external power supplies.

The EVL400W-EUPL7 has also obtained CLEAResult® Plug Load Solutions® 80 PLUS™ certification, a Platinum rating for 115V AC, and 230V AAchieved Gold rank in C.

High efficiency can be achieved under light loads by utilizing the burst mode supported by the installed L4984D and L6699, or the L6699's self-adaptive dead-time, which can reduce the primary side current.

The L4984D and L6699 each feature low standby current and disabled inputs, enabling remote on/off control, and can be used for power sequencing or brownout protection. Additionally, the two devices can interact to disable pre-regulation when operating in burst mode.

The EVL400W-EUPL7 incorporates ST's SRK2001 synchronous rectifier controller to achieve high average and general efficiency across a wide load range. Energy savings from synchronous rectification allow for the use of a small heatsink on the secondary side.

The integrated active high-voltage startup circuit, designed with depletion-type MOSFETs, reduces residual power consumption to a negligible level during normal operation and ensures fast startup times.

The EVL400W-EUPL7, supporting a 12V output and an AC input voltage range of 90V to 264V (45 to 65Hz), provides a medium-power reference design that meets energy saving goals, making it suitable for applications such as ATX power supplies, small servers and workstations, medical equipment, signage, and LED panels.

In addition, because of the low no-load power consumption, an auxiliary Switched-Mode Power Supply (SMPS) is not required, reducing the Bill of Materials (BOM). The EVL400W-EUPL7 is available for purchase now for $180.