Texas Instruments BQ24271RGER

Overview

BQ24271RGER from Texas Instruments is a single-input, single-cell Li-ion battery charger IC with integrated power path management and I²C interface. It delivers up to 1.5 A charge current, supports 4.2–18 V USB input with 6.5 V overvoltage protection, regulates system voltage down to 3.5 V, and enables instant system startup from a deeply discharged or absent battery-used in portable media players and netbooks.

For engineers reviewing the BQ24271RGER datasheet, BQ24271RGER pinout, BQ24271RGER application, or BQ24271RGER equivalent, key selection criteria include its JEITA-compliant NTC monitoring, programmable input current limits (USB100/500/900/1.5A), thermal regulation at 120°C, 0.5% battery voltage regulation accuracy, and compatibility with external discharge FET control via BGATE.

Technical Context

The BQ24271RGER implements a fixed-frequency 1.5 MHz voltage-mode PWM controller with internal compensation, enabling stable operation with low-ESR ceramic output capacitors. Its power path architecture decouples system power (SYS) from battery charging (BAT), allowing simultaneous high-efficiency DC-DC conversion and independent battery charge control.

It features five concurrent regulation loops: constant-current, constant-voltage, thermal regulation (120°C trip), minimum system voltage (3.5 V), and input-based dynamic power management (V_{IN_DPM} adjustable from 4.2–4.76 V). The PSEL pin selects initial USB input current limit (100 mA vs. 1.5 A), distinguishing it from the D+/D− detection used in the BQ24270 variant.

Key Specifications

Pinout & Package

Package: 4 mm × 4 mm, 24-pin QFN (RGE) with exposed thermal pad connected to PGND. Designed for high thermal performance in compact portable layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-cell Li-ion charger with power path applications.

Compared with BQ24270RGER and BQ24295RGER, the BQ24271RGER uniquely balances simplicity (PSEL-driven USB mode selection), JEITA compliance, and proven thermal robustness in QFN-24 packaging-making it optimal for cost-sensitive, thermally constrained portable designs requiring deterministic input current behavior.

Availability

BQ24271RGER is available at Aetrix Electronics and suitable for portable media players, netbooks, and industrial handheld scanners requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for BQ24271RGER 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 battery charging solutions.

The BQ24271RGER belongs to TI's bq242xx family of highly integrated Li-ion chargers designed specifically for space-constrained portable electronics requiring autonomous power path management and JEITA-compliant thermal safety.

FAQ

What is the primary function of the PSEL pin on the BQ24271RGER?

The PSEL pin on the BQ24271RGER is a digital input that selects the initial USB input current limit at power-up: logic high configures 100 mA (USB100 mode) for standard USB ports, while logic low configures 1.5 A (USB150 mode) for AC adapters. This replaces the D+/D− detection used in the BQ24270, simplifying host-side USB source identification. The BQ24271RGER retains full I²C programmability for runtime current limit changes after startup.

Does the BQ24271RGER support charging without a battery connected?

Yes, the BQ24271RGER supports system operation with no battery installed. Its power path architecture regulates the SYS output to a minimum of 3.5 V using the input supply alone, enabling instant system startup and continuous operation. The IC monitors BAT pin voltage and enters high-impedance mode if no valid battery is detected, preventing backfeed or instability. This behavior is confirmed in the datasheet's "System Turn-On with No Battery" application note and Figure 2 typical circuit.

How does the BQ24271RGER implement JEITA-compliant charging?

The BQ24271RGER implements JEITA compliance through its TS pin, which reads a resistor divider from DRV (5.2 V) to GND connected to an NTC thermistor. The internal comparator detects four voltage thresholds corresponding to COLD (≤10°C), COOL (10–25°C), WARM (25–45°C), and HOT (>45°C) zones, each with defined charge voltage and current limits. These thresholds are factory-trimmed and require no external calibration-enabling full JEITA profile enforcement without MCU intervention.

What thermal protection mechanisms are built into the BQ24271RGER?

The BQ24271RGER includes dual thermal protections: (1) junction temperature regulation triggers at 120°C, linearly reducing charge current to maintain die temperature; and (2) thermal shutdown activates at 165°C with 10°C hysteresis. Both functions are hardware-based and operate independently of I²C communication. The QFN-24 (RGE) package's low θ_JA of 32.6°C/W and exposed thermal pad ensure effective heat transfer to the PCB, supporting sustained 1.5 A operation in properly laid-out designs.

Can the BQ24271RGER be used with an external discharge FET?

Yes, the BQ24271RGER supports external discharge FET control via the BGATE pin, which drives the gate of an external P-channel MOSFET connected between BAT and PGND. When enabled, this path provides low-resistance battery discharge-critical for rapid system shutdown or battery isolation. The BGATE output is actively driven low in high-impedance mode and when no input is present, ensuring safe default behavior. This capability is explicitly documented in the "External Discharge FET" section of the datasheet and shown in Figure 2.