Texas Instruments LP8555EVM

Overview

LP8555EVM from Texas Instruments is an evaluation module designed to characterize and validate the LP8555 high-efficiency LED backlight driver IC for tablet LCD displays. It supports up to 12 LED strings, operates from 2.7 V to 20 V input, delivers adaptive dual-boost output voltage control, and enables brightness regulation via I²C, PWM, or hybrid modes. The EVM integrates an MSP430 microcontroller for USB-based GUI control and includes test points, connectors for external LED panels, and configurable power rails.

For engineers reviewing the LP8555EVM datasheet, LP8555EVM hardware setup, LP8555EVM schematic, or LP8555EVM software interface, this module provides full access to register-level configuration (including BRTLO, CONFIG, CURRENT, BOOST), real-time brightness control, fault monitoring via INT pin, and validation of adaptive headroom management across varying LED VF and string counts.

Technical Context

The LP8555EVM implements the LP8555 IC in a fully functional reference design with dual DC-DC boost converters (SW_A/FB_A and SW_B/FB_B), 12 precision current sinks (LEDA1–LEDA6, LEDB1–LEDB6), and integrated LDO (VLDO) for logic supply. It supports three brightness control modes-PWM-only (BRTMODE = 00b), I²C-only (BRTMODE = 01b), and I²C+PWM (BRTMODE = 10/11b)-with programmable start-up sequences, slope-controlled dimming, and auto-detection of active LED strings (2–12).

Power sequencing is managed through the dual-function EN/VDDIO pin, which serves as both enable input and I/O reference voltage (1.7 V threshold). The EVM's 4-layer FR4 board includes dedicated PGND plane (Layer 3), microvias between Layers 1–2, immersion gold finish, and layout-optimized placement of boost inductors (L1/L2), diodes (D1/D2), and input/output capacitors to minimize EMI and support spread-spectrum and phase-shifted switching.

Key Specifications

Availability

LP8555EVM is available at Aetrix Electronics and suitable for LCD backlight development, embedded display system validation, and LED driver IC characterization requiring stable component supply, traceable evaluation hardware, and documented reference design implementation.

Supply support for LP8555EVM 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

Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and power management technologies, with decades of leadership in display driver and LED lighting solutions.

The LP8555EVM belongs to TI's display power evaluation platform family, engineered specifically to accelerate development of high-efficiency, low-noise LCD backlight systems for tablets and portable displays using the LP8555 IC.

FAQ

What is the LP8555EVM used for?

The LP8555EVM is an evaluation module designed to test and validate the LP8555 high-efficiency LED backlight driver IC. It enables engineers to verify dual-boost operation, 12-string current sink performance, adaptive headroom control, brightness regulation via I²C or PWM, and fault response behavior under real-world LCD panel loads. The LP8555EVM includes USB interface, GUI software, and test points for comprehensive signal analysis.

Does the LP8555EVM require external components to operate?

No - the LP8555EVM is a complete, self-contained evaluation platform. It integrates the LP8555 IC, dual boost converters (L1/D1/CIN_A/COUT_A and L2/D2/CIN_B/COUT_B), MSP430 microcontroller, USB interface circuitry, VDDIO selection jumpers, and connectors for external LED boards or LCD panels. Only a 2.7–20 V DC input and USB connection are required to begin evaluation of the LP8555EVM.

How is brightness controlled on the LP8555EVM?

Brightness on the LP8555EVM is controlled via three configurable modes: PWM input (measuring duty cycle on PWM/INT pin), I²C register writes (BRTLO/BTHI registers), or hybrid mode combining both. The Windows GUI provides tabbed controls for Pin, Brightness, LED Driver, Boost, and Other settings - allowing real-time adjustment of BRT[11:0], current limits, boost voltage targets, and ramp timing without firmware changes to the LP8555EVM.

Can the LP8555EVM drive a real LCD panel?

Yes - the LP8555EVM features dedicated connectors (J1–J4) compatible with standard external LED boards or full LCD panels. It supports Kelvin sensing via R13–R26 for accurate current measurement and provides VOUT_A/VOUT_B test points for boost output verification. The LP8555EVM has been validated with 12-string configurations and adapts automatically to 2–12 active strings, making it suitable for direct integration into display subsystem prototyping.

What documentation accompanies the LP8555EVM?

The LP8555EVM ships with the SNVU299 User's Guide, which includes full schematic diagrams, 4-layer PCB layout and stackup details, bill of materials (BOM), power sequencing waveforms, register map definitions (COMMAND, CONFIG, CURRENT, BOOST, etc.), and step-by-step instructions for GUI software setup and usage. The companion LP8555 datasheet (SNVS857) provides electrical specifications, timing diagrams, and application design guidance referenced throughout the LP8555EVM documentation.