Texas Instruments TPS61187RTJR

Overview

TPS61187 from Texas Instruments is a white-LED driver IC for notebook LCD backlight systems, integrating a 40-V/2-A boost regulator, six 30-mA current sinks, and automatic phase-shift PWM dimming control. It operates from 4.5 V to 24 V input, delivers up to 38 V output, supports 100:1 dimming at 20 kHz, and achieves 1.5% typical current matching across strings in notebook display applications.

For engineers reviewing the TPS61187 datasheet, TPS61187 pinout, TPS61187 application, or TPS61187 equivalent, key selection considerations include its dual-mode PWM dimming (phase-shift vs. direct), programmable switching frequency (300 kHz–1 MHz), integrated overvoltage/short/open-LED protection, thermal shutdown, and WQFN-20 package with exposed thermal pad.

Technical Context

The TPS61187 employs current-mode control in its fixed-frequency boost regulator, with integrated loop compensation and adaptive output voltage regulation-maintaining the lowest IFB pin at 350 mV while dynamically adjusting V_OUT to match LED string forward voltage. Its six independent current sinks are precision-matched (±1.5% typ.) and support up to 60 WLEDs in parallel configurations.

Dimming is implemented via two configurable modes: auto phase-shift PWM (programmable FDIM from 100 Hz to 22 kHz using R_FPWM) or direct PWM (100 Hz–50 kHz), both controlled by the external PWM signal applied to the PWM pin. Mode selection is determined by resistor biasing or connection of the RFPWM/MODE pin to VDDIO.

Key Specifications

Pinout & Package

TPS61187 is housed in a 20-pin WQFN (RTJ) package measuring 4.0 mm × 4.0 mm with an exposed thermal pad. The package supports high-power dissipation via PCB copper thermal vias connected to ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS61187, TPS61183RTJR offers pin compatibility but sacrifices dimming mode flexibility, while MAX16832ATI+ trades integration for design adaptability-making TPS61187 optimal for space-constrained, high-efficiency notebook backlight designs requiring dual-mode PWM control.

Availability

TPS61187 is available at Aetrix Electronics and suitable for notebook backlight systems, industrial panel PCs, medical diagnostic monitors, and gaming laptop displays requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TPS61187 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 over 50 years of innovation in high-reliability power conversion solutions.

The TPS61187 belongs to TI's WLED backlight driver product line, engineered specifically for ultra-thin, high-brightness notebook and portable display applications demanding adaptive voltage regulation, precision current matching, and low-noise PWM dimming.

FAQ

What is the maximum number of white LEDs the TPS61187 can drive?

The TPS61187 supports up to 60 white LEDs configured across its six current sinks - for example, 10 LEDs per string in 6 parallel strings. Each sink delivers up to 30 mA, and the 38-V maximum output voltage accommodates typical forward voltages of 3.2–3.6 V per LED. The actual count depends on string configuration, input voltage, and thermal design; the TPS61187 datasheet provides detailed string sizing guidance based on VIN and VOUT headroom.

How does the TPS61187 achieve adaptive output voltage regulation?

The TPS61187 continuously monitors the six IFB pins and regulates its boost output voltage to maintain the lowest IFB pin at 350 mV - the internal reference threshold. This ensures minimal voltage drop across each current sink, reducing power loss and heat generation. As LED forward voltages change with temperature or aging, the TPS61187 dynamically adjusts VOUT to sustain precise current regulation without manual recalibration - a key advantage over fixed-output boost drivers.

Can the TPS61187 operate in both phase-shift and direct PWM dimming modes simultaneously?

No, the TPS61187 operates exclusively in one dimming mode at a time, selected by the RFPWM/MODE pin configuration: a resistor to ground enables phase-shift PWM (with programmable FDIM), while connection to VDDIO forces direct PWM mode. The internal decoder circuit is disabled in direct mode, eliminating duty-cycle reconstruction latency. Attempting simultaneous operation is not supported and may cause undefined behavior or reduced dimming accuracy.

What is the purpose of the OVC pin on the TPS61187?

The OVC (Overvoltage Clamp) pin on the TPS61187 serves as the feedback input for output overvoltage protection. It connects to a resistive divider from the boost output, setting the clamping threshold at 1.95 V (typical). When the divided voltage exceeds this threshold, the TPS61187 disables the power switch to prevent damage to downstream LEDs or components. Unlike standard VFB pins, OVC is dedicated solely to safety-critical overvoltage limiting-not output regulation-and works independently of the IFB current control loop.

Does the TPS61187 require external compensation components for its boost regulator?

No, the TPS61187 integrates full loop compensation for its current-mode boost regulator, eliminating the need for external compensation networks. TI's internal compensation is optimized for stability across the full operating range (4.5–24 V input, up to 38 V output) when used with recommended external components: 10–47 µH inductor, 1–4.7 µF output capacitor, and proper PCB layout grounding. Adding external compensation may destabilize the control loop and is neither required nor recommended.