Toshiba Semiconductor and Storage TB62771FTG,8,EL

Overview

TB62771FTG from Toshiba is a 4-channel constant-current sink LED driver IC with integrated current-mode step-up DC/DC controller, designed for high-power white LED backlighting in large LCD panels. It delivers 20–150 mA per channel with ±2% current accuracy at 100 mA, supports PWM dimming up to 30 kHz, and features built-in LED open/short detection, thermal shutdown, and overvoltage protection.

For engineers reviewing the TB62771FTG datasheet, TB62771FTG pinout, TB62771FTG application, or TB62771FTG equivalent, key selection considerations include its 4.75–40 V input range, RT-settable 200 kHz–2 MHz switching frequency, 0.5 V minimum OUT terminal voltage regulation, ±1.5% inter-channel current matching, and P-WQFN20-0404-0.50-002 package with exposed thermal pad.

Technical Context

The TB62771FTG integrates a current-mode boost controller with independent 4-channel constant-current sinks, where feedback dynamically shifts between OVP×95% (standby) and minimum OUT terminal voltage (0.5 V, operation mode). Its error amplifier regulates output based on CS-sensed MOSFET current and COMP-compensated loop stability, while slope compensation (45–55 µA·f_SW) ensures stable operation across 200 kHz–2 MHz.

Dimming control uses digital PWM input (DIM) with 330 ns minimum pulse width, enabling phase-shifted channel activation (100 ns typical delay) to suppress inrush current. Fault management includes latch-type FLT output for LED open/short, thermal shutdown, OCP (via CS), UVLO on VIN/VCC, and configurable OVP/LED short thresholds via external resistors on OVP and RSDT pins.

Key Specifications

Pinout & Package

Package: P-WQFN20-0404-0.50-002 - 4 mm × 4 mm, 0.5 mm pitch, 20-pin thermally enhanced quad flat no-lead with exposed pad for efficient heat dissipation in high-current LED driver applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL8862SP-13 and MPQ4425AGU-AEC1-P, the TB62771FTG uniquely combines 4-channel synchronized sink control, RT-programmable switching frequency, and automatic OVP/min-OUT feedback mode switching-making it the only solution that simultaneously meets high-current uniformity, EMI reduction, and adaptive fault-aware operation in large-area LCD backlighting.

Availability

TB62771FTG is available at Aetrix Electronics and suitable for large-screen LCD backlighting, industrial HMI displays, and automotive infotainment systems requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.

Supply support for TB62771FTG 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

Toshiba Electronic Devices & Storage Corporation designs high-reliability analog and power semiconductors for automotive, industrial, and consumer applications, with emphasis on energy efficiency and functional safety.

The TB62771FTG belongs to Toshiba's BiCD LED driver product line, engineered specifically for high-power white LED backlighting in large-format LCD panels-prioritizing current accuracy, thermal resilience, and integrated fault protection.

FAQ

What is the maximum allowable switching frequency for TB62771FTG, and how is it set?

The TB62771FTG supports a maximum switching frequency of 2.0 MHz, set by connecting an external resistor between the RT pin and AGND. The relationship is defined as RT = 7.350 × 10⁹ / f_SW, where RT is in ohms and f_SW is in Hz. For 2.0 MHz operation, RT ≈ 3.675 kΩ. This high-frequency capability allows use of smaller magnetic components and reduces output ripple in space-constrained LCD backlight designs using TB62771FTG.

How does TB62771FTG handle LED open-circuit faults, and what is the response time?

TB62771FTG detects LED open circuits by monitoring OUT terminal voltage during OVP-triggered conditions-if any OUT voltage remains ≤0.2 V (typ.) while V_LED rises, that channel is disabled and FLT is pulled low. Detection occurs within one switching cycle after OVP event confirmation, typically <5 µs. The TB62771FTG continues regulating remaining healthy channels, ensuring partial backlight functionality instead of full system shutdown.

Can TB62771FTG operate with a 3.3 V microcontroller PWM signal on the DIM pin?

Yes, TB62771FTG accepts 3.3 V logic on the DIM pin: its VIH(DIM) minimum is 2.1 V, and VIL(DIM) maximum is 0.8 V, making it compatible with standard 3.3 V CMOS outputs. The TB62771FTG also tolerates DIM pulses as narrow as 330 ns, supporting high-resolution dimming control from modern MCUs without additional level-shifting circuitry.

What thermal performance can be expected from TB62771FTG in its P-WQFN20 package?

In the P-WQFN20-0404-0.50-002 package with proper PCB layout (74 mm × 74 mm, 4-layer FR-4), TB62771FTG achieves a junction-to-ambient thermal resistance (R_th(j-a)) of 39 °C/W. At 150 mA per channel (600 mA total load) and 12 V input, typical power dissipation is ~1.8 W-resulting in ~70 °C junction rise above ambient. This allows reliable operation up to +85 °C ambient without forced airflow when using the exposed pad for thermal conduction.

Does TB62771FTG require external compensation components, and where are they connected?

Yes, TB62771FTG requires external RC compensation on the COMP pin to stabilize the boost converter's feedback loop. A resistor and capacitor must be connected between COMP and AGND-values determined by the selected switching frequency, output voltage, and inductor characteristics. The TB62771FTG datasheet provides design equations and example values; omitting this network causes instability, oscillation, or poor transient response in the regulated V_LED output.