STMicroelectronics STEVAL-LLL004V1

Overview

STEVAL-LLL004V1 from STMicroelectronics is a 75 W digitally controlled LED driver reference design featuring dual constant-current outputs (buck and inverse-buck topologies), transition-mode PFC, and STM32F071CB-based digital control for flicker-free dimming down to 0.5%. It delivers 500 mA ±2.5% per channel driving 16–24 white LEDs (3.3 V each) across 85–265 VAC input.

For engineers reviewing the STEVAL-LLL004V1 datasheet, STEVAL-LLL004V1 pinout, STEVAL-LLL004V1 application, or STEVAL-LLL004V1 equivalent, this board enables evaluation of digital control advantages in LED drivers-including adaptive loop tuning, THD < 20%, PFC > 0.97, EN55022 Class B compliance, and dual-topology comparison under real-world AC line and dimming conditions.

Technical Context

The board implements a two-stage architecture: a front-end transition-mode PFC stage using STD11N60M2-EP MOSFET and VIPER012LS auxiliary converter, followed by two independent DC-DC stages-standard buck and inverse buck-both operating in transition mode and synchronized via STM32F071CB's Timer Link feature.

Digital control leverages the STM32F071CB's advanced timer (TIMER1), embedded CEC, and hardware peripherals to execute real-time PI regulation for PFC, current-mode control for both DC-DC converters, and simultaneous analog (0–10 V) and digital (push-button) dimming with 12-bit resolution and soft-start sequencing.

Key Specifications

Availability

STEVAL-LLL004V1 is available at Aetrix Electronics and suitable for LED lighting development, power electronics prototyping, and digital control algorithm validation requiring stable component supply, repeatable reference performance, and production-ready topology evaluation.

Supply support for STEVAL-LLL004V1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing microcontrollers, power devices, analog ICs, and sensors for industrial, automotive, and consumer applications.

This board belongs to ST's LED Driver Reference Design portfolio, created to accelerate adoption of digital control in high-efficiency, high-PF, low-THD solid-state lighting systems targeting commercial retrofit and smart building applications.

FAQ

What is the primary function of the STM32F071CB on this board?

The STM32F071CB serves as the central digital controller, executing real-time PFC regulation, dual DC-DC current-loop control, 0–10 V and push-button dimming decoding, soft-start sequencing, and safety monitoring-including open-circuit, short-circuit, and overload detection-with hardware timer synchronization between buck and inverse-buck stages.

Can STEVAL-LLL004V1 drive mixed LED strings with different forward voltages?

No-it is configured for two identical output channels, each delivering 500 mA ±2.5% into 16–24 white LEDs rated at 3.3 V nominal. The fixed current regulation and topology layout do not support asymmetric or multi-Vf string configurations without hardware modification and firmware re-tuning.

Does this board support DALI or PWM dimming interfaces?

No-dimming is limited to analog 0–10 V input and digital push-button control. DALI, PWM, or wireless protocols (e.g., Bluetooth Mesh, Zigbee) are not implemented; those require external gateways or custom firmware extensions beyond the reference design scope.

Is the PFC stage isolated from the DC-DC outputs?

No-the PFC stage generates a non-isolated high-voltage DC bus (~400 V) that feeds both buck and inverse-buck converters. Output channels share ground with the AC input neutral, making the entire design non-isolated and intended for Class I (earthed) luminaire applications only.