Texas Instruments BQ29200DRBT

Overview

BQ29200DRBT from Texas Instruments is a secondary overvoltage protection IC for 2-series Li-ion battery packs, integrating precision voltage monitoring and automatic cell imbalance correction. It features ±25 mV overvoltage detection accuracy (0°C–60°C), 4.35 V fixed OVP threshold, <3 µA supply current in normal operation, and internal balancing up to 15 mA. It serves as critical second-level safety protection in portable power tools and netbook battery packs.

For engineers reviewing the BQ29200DRBT datasheet, BQ29200DRBT pinout, BQ29200DRBT application, or BQ29200DRBT equivalent, key selection criteria include verified 4.35 V OVP threshold, ±30 mV/0 mV cell balance enable/disable hysteresis, external capacitor-controlled delay timing (9 s/µF nominal), thermal performance in 3.0 mm × 3.0 mm VSON-8 package, and compatibility with 2-cell stack topologies requiring dual VCx sensing and active CB_EN control.

Technical Context

The BQ29200DRBT continuously monitors VC1 (bottom cell) and VC2 (top cell) against a factory-trimmed 4.35 V reference using high-accuracy comparators with ±25 mV tolerance over 0°C–60°C. Upon overvoltage detection, it initiates a programmable delay via external capacitor on CD pin before asserting high-level OUT signal.

Cell balancing is triggered when voltage difference exceeds ±30 mV and disabled at ≤0 mV, controlled by active-low CB_EN. Internal balancing uses dedicated RCB1/RCB2 paths with switch resistance of 2.5–3.0 Ω, supporting up to 15 mA per cell; external balancing is enabled via discrete FETs driven by VC1_CB and OUT signals.

Key Specifications

Pinout & Package

Package: 8-pin VSON (DRB), 3.00 mm × 3.00 mm body size, exposed thermal pad (PWR PAD) connected to GND for thermal management.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar secondary overvoltage protection applications.

Compared with BQ29200DRBT, BQ29209DRBT offers identical functionality with a lower OVP threshold for conservative designs, while BD1400GUL provides basic protection without balancing - making BQ29200DRBT the optimal choice when autonomous cell matching and precise 4.35 V cutoff are required in minimal footprint.

Availability

BQ29200DRBT is available at Aetrix Electronics and suitable for power tools, netbook computers, portable medical devices, and battery backup systems requiring stable component supply across industrial temperature ranges and long lifecycle support.

Supply support for BQ29200DRBT 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 company specializing in analog and embedded processing technologies, with leadership in battery management and power ICs.

The bq2920x product line delivers secondary protection and cell balancing for 2-series Li-ion battery packs, designed specifically for safety-critical portable equipment where hardware-based redundancy and autonomous voltage correction are mandatory.

FAQ

What is the exact overvoltage protection threshold for BQ29200DRBT?

The BQ29200DRBT has a factory-programmed fixed overvoltage protection threshold of 4.35 V, with ±25 mV accuracy over 0°C to 60°C ambient temperature. This value is laser-trimmed during manufacturing and does not require external configuration. The BQ29200DRBT datasheet specifies no user-adjustable OVP setting - the 4.35 V threshold is immutable and validated across production lots.

How does BQ29200DRBT initiate and terminate cell balancing?

The BQ29200DRBT initiates cell balancing when the voltage difference between VC2 and VC1 exceeds ±30 mV and terminates it when the difference falls to ≤0 mV, both measured with CB_EN pulled low. Balancing is disabled entirely when CB_EN rises above 2.2 V. The BQ29200DRBT uses internal MOSFET switches (RCB1/RCB2) to shunt current through external resistors, supporting up to 15 mA per cell without external FETs.

Can BQ29200DRBT operate without an external delay capacitor?

No - the BQ29200DRBT requires an external capacitor on the CD pin to set overvoltage response timing. Without it, the internal delay timer cannot function, and the OUT pin will not assert high upon overvoltage detection. The BQ29200DRBT datasheet specifies minimum CD capacitance of 0.1 µF and recommends values between 0.1 µF and 1 µF to achieve 1–10 s delay windows using the 9 s/µF scale factor.

What is the role of the PWR PAD on BQ29200DRBT?

The PWR PAD on the BQ29200DRBT is an exposed thermal pad on the underside of the VSON-8 package, electrically connected to GND. It must be soldered to a PCB copper pour tied to system ground to ensure proper thermal dissipation and electrical stability. The BQ29200DRBT thermal data shows RθJB = 19.3 °C/W - omitting PWR PAD connection degrades junction-to-board thermal resistance and risks exceeding maximum junction temperature under sustained balancing current.

Does BQ29200DRBT support external cell balancing beyond its internal 15 mA limit?

Yes - the BQ29200DRBT supports external cell balancing using discrete FETs controlled by VC1_CB and OUT signals. When CB_EN is low, VC1_CB drives the gate of an external N-channel FET to discharge the bottom cell, while OUT can drive a high-side switch for top-cell balancing. The BQ29200DRBT datasheet provides Figure 11 showing RCLAMP and RCB_EXT resistor networks to implement currents beyond 15 mA without modifying the IC's internal operation.