STMicroelectronics STEVAL-TLL001V1

Overview

STEVAL-TLL001V1 from STMicroelectronics is an evaluation board built around the STLD40D boost LED controller IC, designed to drive up to 10 white LEDs in series at 37 V output and 20 mA constant current, operating from 3.0–5.5 V input with PFM control, adjustable peak current limit, and PWM dimming support via the EN pin.

For engineers reviewing the STEVAL-TLL001V1 datasheet, STEVAL-TLL001V1 schematic, STEVAL-TLL001V1 application, or STEVAL-TLL001V1 equivalent, this board enables rapid validation of high-efficiency, low-noise white LED lighting solutions for portable displays, backlighting, and battery-powered illumination systems requiring precise current regulation and compact boost topology.

Technical Context

The STEVAL-TLL001V1 implements a discontinuous conduction mode (DCM) PFM-controlled boost converter using the STLD40D IC, which integrates a fixed minimum OFF-time switch to stabilize switching frequency across load and input variations. Regulation is achieved by sensing LED current through an external sense resistor (RLED) and adjusting switching duty via peak-current limiting.

It supports logic-level enable/disable control and low-frequency PWM dimming by modulating the EN pin, while providing over-voltage protection with automatic restart and shutdown current below 1 µA - critical for battery longevity in portable applications.

Key Specifications

Availability

STEVAL-TLL001V1 is available at Aetrix Electronics and suitable for portable display backlighting, handheld medical device illumination, battery-powered signage, and industrial status lighting requiring stable component supply and rapid prototyping capability.

Supply support for STEVAL-TLL001V1 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, delivering microcontrollers, analog ICs, power management, and sensor solutions for industrial, automotive, and consumer markets.

The STEVAL-TLL001V1 belongs to ST's LED lighting evaluation platform family, engineered to accelerate design-in of efficient, compact, and dimmable LED driver solutions for space-constrained, battery-sensitive applications.

FAQ

What is the maximum number of white LEDs the STEVAL-TLL001V1 can drive in series?

The board supports up to 10 white LEDs in series, based on its 37 V maximum output voltage and typical forward voltage of ~3.7 V per LED. This configuration delivers 20 mA constant current with full regulation, verified in ST's reference schematic and test reports.

Does the STEVAL-TLL001V1 support analog dimming?

No - the board implements only PWM dimming via the EN pin. Analog dimming is not supported because the STLD40D regulates LED current solely through peak-current limiting and does not provide a dedicated I_ADJ or DAC-controlled reference input.

Can the STEVAL-TLL001V1 operate from a 3.3 V supply?

Yes - the STLD40D IC operates down to 3.0 V input, so the board functions reliably at 3.3 V. Efficiency remains above 85% at 3.3 V input driving 8-series LEDs, as confirmed in ST's characterization data (Data Brief Rev 1, p.2).

Is an external inductor required, and what value is recommended?

Yes - the board requires an external power inductor. The reference design specifies a 4.7 µH, 1.5 A saturation current shielded inductor (e.g., Würth Elektronik 744040470), selected to ensure DCM operation and minimize EMI across the 3–5.5 V input range.