Texas Instruments BQ24120RHLRG4

Overview

BQ24120RHLRG4 from Texas Instruments is a single-chip, synchronous-switched-mode Li-ion/Li-polymer charge-management IC supporting 1-cell (4.2 V) standalone charging. It integrates 2-A power FETs, 1.1-MHz fixed-frequency PWM control, ±1% voltage regulation accuracy, high-side current sensing via SNS pin, and dual-status open-drain outputs (STAT1/STAT2) for charge-in-progress and charge-done indication in portable media players and industrial handheld devices.

For engineers reviewing the BQ24120RHLRG4 datasheet, BQ24120RHLRG4 pinout, BQ24120RHLRG4 application, or BQ24120RHLRG4 equivalent, key selection criteria include its 4.2-V fixed output voltage, 2-A max charge current capability, integrated thermal shutdown and battery temperature monitoring (via TS/VTSB), programmable precharge/termination thresholds, and VQFN-20 (3.5 mm × 4.5 mm) thermally enhanced package with exposed thermal pad tied to VSS.

Technical Context

The BQ24120RHLRG4 implements a voltage-mode synchronous buck controller with 0%–100% duty cycle range, feed-forward line regulation, and internal Type-III compensation enabling stable operation with low-ESR ceramic output capacitors. Its dual-MOSFET architecture uses a high-side P-channel switch (with VCC−6 V gate drive) and low-side N-channel switch, eliminating bootstrap requirements while supporting reverse leakage protection when VIN < VBAT.

Charge sequencing follows three phases-preconditioning (15–200 mA, set by ISET2), constant-current fast charge (150–2000 mA, set by ISET1), and constant-voltage regulation (4.2 V ±1%)-with termination triggered at 15–200 mA taper current and backed up by a programmable 25–572-minute safety timer (via TTC capacitor). Battery temperature qualification uses an NTC thermistor biased by the 3.15-V VTSB regulator and monitored against LTF (73.5% of VTSB), HTF (34.4% of VTSB), and TCO (29.3% of VTSB) thresholds.

Key Specifications

Pinout & Package

VQFN-20 package (3.5 mm × 4.5 mm) with exposed thermal pad electrically connected to VSS; requires soldering pad to system ground plane for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Li-ion charge management applications.

Compared with BQ24123RHLRG4 and BQ24125RHLRG4, the BQ24120RHLRG4 provides optimized cost and simplicity for fixed 4.2-V single-cell applications, eliminating unused pins (CELLS, FB) and simplifying layout-while retaining identical thermal performance, EMI behavior, and protection features.

Availability

BQ24120RHLRG4 is available at Aetrix Electronics and suitable for portable media players, industrial handheld scanners, medical point-of-care monitors, and portable DVD players requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for BQ24120RHLRG4 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 delivering analog and embedded processing solutions with emphasis on power management, signal chain, and connectivity technologies.

The bqSWITCHER™ series-including BQ24120RHLRG4-is designed specifically for high-efficiency, thermally robust, EMI-optimized Li-ion/Li-polymer charging in space-constrained portable electronics.

FAQ

What is the maximum continuous charge current supported by the BQ24120RHLRG4?

The BQ24120RHLRG4 supports up to 2000 mA continuous charge current, programmable via a resistor connected between ISET1 pin and VSS. This value is derived from the 1-V reference and 1000 V/A scaling factor specified in the electrical characteristics table, and assumes proper thermal management using the exposed thermal pad and recommended PCB copper area.

Does the BQ24120RHLRG4 require external MOSFETs for charging?

No, the BQ24120RHLRG4 integrates both high-side P-channel and low-side N-channel power MOSFETs, eliminating the need for external switches. Its synchronous buck architecture supports up to 2-A charge current with typical RDS(on) values of 450 mΩ (high-side) and 130 mΩ (low-side) at VCC ≥ 7 V, enabling compact, low-component-count charger designs.

How does the BQ24120RHLRG4 handle battery temperature monitoring?

The BQ24120RHLRG4 monitors battery temperature via the TS pin using an NTC thermistor and voltage divider powered by the internal 3.15-V VTSB regulator. It enforces three thresholds-LTF (73.5% of VTSB), HTF (34.4% of VTSB), and TCO (29.3% of VTSB)-to suspend charging outside safe thermal ranges, with 30-ms deglitching to prevent false triggers.

Can the BQ24120RHLRG4 be used for two-cell Li-ion battery packs?

No, the BQ24120RHLRG4 is factory-configured for fixed 4.2-V single-cell operation only. For two-cell (8.4-V) support, Texas Instruments specifies the BQ24123RHLRG4, which uses the CELLs pin to select between 4.2 V and 8.4 V output. The BQ24120RHLRG4 lacks the CELLs pin functionality and will not regulate correctly at higher voltages.

What protection features are built into the BQ24120RHLRG4?

The BQ24120RHLRG4 includes overvoltage protection (117% of 4.2 V), thermal shutdown (165°C trip), short-circuit current limiting (35–65 mA), battery undervoltage detection (VSHORT = 2.0 V/cell), cycle-by-cycle current limit (3.6 A peak), and reverse leakage prevention when VIN < VBAT. All protections trigger automatic shutdown without requiring external circuitry.