Texas Instruments LP8545SQE/NOPB

Overview

LP8545SQE/NOPB from Texas Instruments is a high-efficiency white LED backlight driver IC with integrated 22 V boost converter and six programmable current sinks. It delivers up to 40 V output, supports 8–13-bit PWM dimming resolution with dithering, and features adaptive output voltage control, phase-shift PWM for reduced ripple/noise, and I²C + PWM dual brightness control. It targets notebook LCD backlight systems requiring precise, low-noise, thermally robust LED current regulation.

For engineers reviewing the LP8545SQE/NOPB datasheet, LP8545SQE/NOPB pinout, LP8545SQE/NOPB application, or LP8545SQE/NOPB equivalent, key selection considerations include its 6-channel constant-current sink architecture, WQFN-24 package thermal performance, 156–1250 kHz selectable boost switching frequency, internal EEPROM configuration storage, and VSYNC-synchronized PWM capability for flicker-free display timing alignment.

Technical Context

The LP8545SQE/NOPB integrates a high-voltage DC/DC boost converter with adaptive feedback (FB pin) that dynamically adjusts output voltage to match LED string forward voltage-minimizing power loss. Its six current sinks support independent 8-bit current programming and synchronized 13-bit PWM dimming with proprietary phase-shift control to reduce peak inductor current and audible noise.

It implements a dual-clock architecture: a 5 MHz internal oscillator (scalable to 40 MHz via PLL) drives PWM generation, while optional VSYNC synchronization ensures pixel-refresh-aligned backlight modulation. Internal EEPROM stores configuration-including PWM frequency, temperature thresholds, slope timing, and dither settings-enabling minimal external component count and no boot-time host initialization.

Key Specifications

Pinout & Package

LP8545SQE/NOPB uses a 4 mm × 4 mm, 0.8 mm height WQFN-24 package (TI package code RTW) with exposed thermal pad for enhanced power dissipation in space-constrained notebook designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED backlight driver applications.

Compared with TPS61165DRVR and MAX16832ATP+, the LP8545SQE/NOPB uniquely integrates adaptive boost, VSYNC-locked multi-channel PWM, EEPROM-based configuration, and programmable thermal derating-making it the only option for high-fidelity, thermally constrained, and timing-critical notebook and industrial display backlights.

Availability

LP8545SQE/NOPB is available at Aetrix Electronics and suitable for notebook backlight systems, industrial HMI panels, medical diagnostic monitors, and automotive infotainment displays requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LP8545SQE/NOPB 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 leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in display power solutions.

The LP8545SQE/NOPB belongs to TI's high-efficiency LED backlight driver product line, designed specifically for space-constrained, thermally demanding LCD applications in portable computing and industrial displays where precision dimming, low noise, and autonomous fault handling are critical.

FAQ

What is the maximum LED string voltage supported by the LP8545SQE/NOPB?

The LP8545SQE/NOPB supports a maximum boost output voltage of 40 V, verified per absolute maximum ratings (V_OUT = 40 V). This allows driving up to 12 white LEDs in series (assuming 3.3 V typical forward voltage) while maintaining margin for voltage variation and temperature drift. The adaptive FB loop continuously adjusts VOUT to the minimum necessary level, improving efficiency across all brightness levels and input voltages.

Does the LP8545SQE/NOPB require an external microcontroller to configure its EEPROM settings?

No, the LP8545SQE/NOPB does not require an external microcontroller for initial configuration. Its internal EEPROM retains all settings-including PWM frequency, LED current, thermal thresholds, and dither mode-across power cycles. Configuration can be performed once via I²C during manufacturing or system bring-up; thereafter, the LP8545SQE/NOPB operates autonomously using stored parameters without host intervention.

Can the LP8545SQE/NOPB drive LED strings with different forward voltages across its six channels?

Yes, the LP8545SQE/NOPB supports mixed LED string configurations. Each OUTx pin operates as an independent constant-current sink with shared adaptive boost output. As long as the highest string's forward voltage remains within the 40 V limit-and all strings connect to the same VOUT rail-the device maintains accurate current regulation per channel. Matching accuracy remains ±0.5% (typ.) regardless of inter-string Vf variance.

How does the phase-shift PWM feature in the LP8545SQE/NOPB reduce audible noise?

The LP8545SQE/NOPB's phase-shift PWM staggers the turn-on timing of its six LED channels by fixed intervals, distributing the high-di/dt current demand across the switching period. This lowers peak input capacitor ripple current by up to 40%, reducing mechanical vibration in ceramic capacitors and inductor windings-eliminating the 1–3 kHz whine common in non-phase-shifted LED drivers. No additional filtering components are required.

What fault conditions does the LP8545SQE/NOPB detect and report via the FAULT pin?

The LP8545SQE/NOPB asserts the open-drain FAULT pin low for four confirmed conditions: (1) open-circuit detection on any LED channel (OUT1–OUT6), (2) short-circuit detection on any LED channel, (3) junction temperature exceeding the programmable thermal shutdown threshold (125°C typ.), and (4) VIN undervoltage lockout (UVLO) activation. All faults are latched until cleared by toggling EN or power cycling, and corresponding status bits are accessible via I²C register reads.