Texas Instruments BQ24155RGYR

Overview

BQ24155RGYR from Texas Instruments is a fully integrated, I²C-programmable, synchronous switch-mode Li-ion/Li-polymer battery charger IC for single-cell portable devices. It delivers up to 1.25 A charge current, supports USB-compliant input current limiting (100 mA/500 mA), regulates charge voltage from 3.5 V to 4.44 V with ±0.5% accuracy at 25°C, and operates in a 3.5 mm × 3.5 mm 14-pin QFN package. It enables fast charging in mobile phones and MP3 players while maintaining thermal regulation and robust overvoltage protection.

For engineers reviewing the BQ24155RGYR datasheet, BQ24155RGYR pinout, BQ24155RGYR application, or BQ24155RGYR equivalent, key selection considerations include its 3 MHz fixed-frequency PWM controller, programmable safety timer (32-minute/32-second modes), integrated power FETs, I²C-compatible interface (up to 3.4 Mbps), and automatic high-impedance mode for low-power standby operation.

Technical Context

The BQ24155RGYR implements a voltage-mode synchronous PWM controller operating at 3 MHz with 0%–99.5% duty cycle control, featuring feed-forward line regulation and internal Type-III compensation. It integrates dual high-side N-FETs (Q1 reverse-blocking, Q2 switching) and one low-side N-FET (Q3), with bootstrap gate drive for Q2 and charge-pump drive for Q1.

Four concurrent regulation loops-input current, charge current, charge voltage, and junction temperature (thermal regulation begins at ~125°C)-dynamically arbitrate control during charging. Input current limiting is enforced via external sense resistor (RSNS) and ISEL pin logic, while termination is determined by programmable ITERM threshold and recharge hysteresis (VOREG − VRCH).

Key Specifications

Pinout & Package

Package: 14-pin QFN (RGY), 3.5 mm × 3.5 mm, exposed thermal pad connected to PGND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGTR, BQ24155RGYR delivers >30% higher efficiency and eliminates external power FETs; compared with BQ24195LRGER, it offers smaller footprint and simpler I²C configuration for USB-focused implementations where 1.25 A and 6 V max input are sufficient.

Availability

BQ24155RGYR is available at Aetrix Electronics and suitable for smartphone power management, MP3 player battery charging, handheld diagnostic tools, USB-powered industrial sensor nodes, and portable medical devices requiring stable component supply and long-term lifecycle support.

Supply support for BQ24155RGYR 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, embedded processing, and wireless technologies for industrial, automotive, and personal electronics markets.

The BQ24155RGYR belongs to TI's bqSwitcher™ battery management product line, designed specifically for space-constrained, USB-compliant portable devices requiring high-efficiency switch-mode charging with minimal external components.

FAQ

What is the maximum continuous charge current supported by the BQ24155RGYR?

The BQ24155RGYR supports a programmable continuous charge current up to 1250 mA, adjustable via I²C interface. This value is achievable under recommended operating conditions (VBUS = 5 V, TJ ≤ 85°C) with appropriate thermal design-including proper PCB copper area under the exposed thermal pad-and a 68 mΩ current-sense resistor. The actual delivered current depends on input voltage, battery voltage, and thermal headroom; the device automatically reduces current above ~125°C to maintain safe operation.

How does the BQ24155RGYR handle USB input current limiting?

The BQ24155RGYR implements USB input current limiting through two complementary mechanisms: hardware-based selection via the ISEL pin (100 mA when low, 500 mA when high), and software-controlled precision regulation via I²C registers. During boot-up with no I²C communication, ISEL sets the default limit; once initialized, the host can override this value with ±5% accuracy. The device continuously monitors VBUS and adjusts switching duty cycle to enforce the programmed limit without external circuitry.

Can the BQ24155RGYR operate without a battery connected?

Yes, the BQ24155RGYR supports "power-up without battery" functionality. When AUXPWR is unconnected or at 0 V and VBUS is applied, the device powers internal circuitry from VBUS and asserts PMID, enabling system-level power delivery. In this state, STAT remains high-impedance, and the charger remains disabled until a valid battery voltage is detected on AUXPWR. This capability allows host systems to initialize and communicate via I²C before battery insertion-critical for field-serviceable or modular devices.

What protection features are integrated into the BQ24155RGYR?

The BQ24155RGYR integrates six core protections: input overvoltage protection (6.5 V trip), output overvoltage protection (117% of programmed VOREG), thermal regulation (~125°C), thermal shutdown (165°C), short-circuit detection (2.0 V battery threshold), and reverse leakage prevention via integrated back-to-back N-FETs. All protections trigger automatic shutdown and assert a 128 µs pulse on the STAT pin. No external components are required to enable these functions-the protection thresholds and responses are fixed in silicon and verified per JEDEC standards.

Is the BQ24155RGYR pin-compatible with other devices in the bq2415x family?

Yes, the BQ24155RGYR shares identical pinout, package (14-pin QFN RGY), and functional pin assignments with the BQ24150RGYR and BQ24153RGYR. Differences lie solely in factory-programmed default register values and minor feature enablement (e.g., BQ24153 lacks I²C address flexibility). This allows direct substitution in existing designs without PCB revision-provided firmware initializes all critical registers explicitly, as default behavior may vary across variants.