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Texas Instruments BQ29412PWR
- Part No.:
- BQ29412PWR
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
BQ29412PWR.pdf
- Description:
- IC BATT PROT LI-ION 2-4CL 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,296
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Product details
Overview
BQ29412PWR from Texas Instruments is a secondary overvoltage protection IC for 2-, 3-, or 4-cell Li-ion battery packs, featuring a fixed 4.45 V per-cell overvoltage threshold, <2 µA supply current, and programmable delay via external capacitor on CD pin. It monitors individual cell voltages (VC1–VC4), drives an external N-channel FET to blow a fuse upon overvoltage, and operates across –40°C to 110°C.
For engineers reviewing the BQ29412PWR datasheet, BQ29412PWR pinout, BQ29412PWR application, or BQ29412PWR equivalent, this device is selected for second-level cell-level voltage monitoring in portable power systems where precision, ultra-low quiescent current, and robust pulse-charge immunity are required.
Technical Context
The BQ29412PWR implements a precision voltage comparator bank with internal reference to detect overvoltage on any of four cell inputs (VC1–VC4), triggering a controlled delay circuit that charges an external capacitor at 0.18 µA until 1.2 V is reached at CD pin. Its output (OUT) transitions high to activate external protection hardware only after full delay expiration.
It features high power supply ripple rejection and stable operation during pulse charging, with differential input tolerance up to ±8 V between adjacent VC pins and absolute input range up to 28 V. The device supports flexible cell configurations (2S–4S) via direct series connection of VC pins and includes built-in hysteresis (320 mV) to prevent oscillation near trip point.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Overvoltage Threshold | 4.45 V per cell - precise fixed trip point for second-level Li-ion cell protection, minimizing false triggers while ensuring safety margin below typical 4.5 V max cell voltage. |
| Supply Current (ICC) | <2 µA - enables multi-year battery pack standby life without compromising protection readiness. |
| Delay Time Programmability | Set by external CD capacitor (e.g., 0.22 µF → 1–2 s delay) - allows system-level tuning of response time to distinguish transient spikes from hazardous overvoltage events. |
| Input Voltage Range (VCn) | –0.3 V to 28 V - supports wide battery stack voltage and tolerates reverse-bias or floating-cell conditions during pack assembly or fault states. |
| Operating Temperature | –40°C to 110°C - qualified for use in demanding portable instrumentation and notebook battery packs exposed to thermal cycling. |
| Overvoltage Accuracy | ±25 mV at 25°C, ±50 mV at –20°C to 85°C - ensures reliable trip consistency across production lots and environmental conditions. |
| Output Drive Capability | High-level output ≥1.5 V at 40 µA load - sufficient to reliably drive gate of discrete NCH FET in fuse-blowing protection path. |
Pinout & Package
TSSOP-8 (PW) package, 3.0 mm × 4.4 mm, 1.2 mm max height, lead pitch 0.65 mm, RoHS-compliant NiPdAu finish, MSL Level-1 (260°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VC1) | Most positive cell voltage sense | Connects to top of 4S stack or shared node in 2S/3S; must be wired before VC2–VC4 to prevent false trigger during power-up. |
| 2 (VC2) | Second most positive cell voltage sense | Monitors voltage between cells 1 and 2 in 4S; tied to VC1 in 3S configuration per TI application guidance. |
| 3 (VC3) | Third most positive cell voltage sense | Monitors voltage between cells 2 and 3 in 4S; tied to VC1/VC2 in 2S configuration. |
| 4 (GND) | Ground reference | System ground return for all internal comparators and CD capacitor discharge path; must be low-impedance. |
| 5 (VC4) | Least positive cell voltage sense | Connects to bottom of stack (cell 4 cathode in 4S); tied to GND in 2S/3S per TI diagrams. |
| 6 (CD) | Capacitor delay timer input | Charged at 0.18 µA; reaches 1.2 V to trigger OUT; clamped to GND if overvoltage clears before timeout. |
| 7 (VDD) | Power supply input | Accepts 4 V to 25 V - powered directly from battery stack or regulated auxiliary rail; includes internal filtering. |
| 8 (OUT) | Protection output driver | Open-drain compatible; pulls high to enable external NCH FET; returns low only after all cells fall below (VPROTECT – Vhys). |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 4.45 V overvoltage threshold | Eliminates external resistor network calibration; guarantees consistent trip point across temperature and lifetime without drift compensation. |
| Programmable overvoltage delay | Enables system-level rejection of charge termination spikes or measurement transients using a single external capacitor (0.22 µF typical). |
| Ultra-low ICC < 2 µA | Preserves battery capacity during long-term storage; avoids parasitic drain that could deplete protected packs over months. |
| Stable under pulse charge | Maintains accurate cell voltage monitoring even during high-frequency CC/CV switching, preventing nuisance trips during normal charging. |
| High ripple rejection | Rejects >60 dB of supply noise - critical when VDD is derived from noisy battery rails or shared power domains. |
Applications
| Portable Notebook Battery Packs | Medical Portable Instrumentation |
|---|---|
Use Scenario: Integrated into smart battery packs for ultrabooks and 2-in-1 devices requiring dual-layer protection. IC Role / Device Role / Timing Role: Second-level hardware overvoltage monitor acting independently of primary fuel gauge IC, asserting OUT only after confirmed sustained overvoltage. Use Value: Prevents thermal runaway by blowing fuse before cell voltage exceeds 4.45 V, meeting UL 2054 and IEC 62133 safety compliance requirements. |
Use Scenario: Used in battery-powered handheld diagnostic tools with strict field-reliability and zero-failure mandates. IC Role / Device Role / Timing Role: Standalone analog protection layer that remains active during MCU sleep or firmware reset, ensuring continuous cell supervision. Use Value: Guarantees fail-safe shutdown independent of software control, satisfying ISO 13485 design assurance for Class II medical devices. |
| Industrial Handheld Scanners | Professional Power Tools |
Use Scenario: Deployed in ruggedized barcode scanners operating in warehouses with wide ambient temperature swings. IC Role / Device Role / Timing Role: Monitors individual Li-ion cells during high-current pulsed operation (e.g., laser activation), rejecting transient spikes. Use Value: Delivers reliable protection across –40°C to 110°C without calibration drift, extending field service life beyond 5 years. |
Use Scenario: Embedded in cordless drill/driver battery packs subjected to repeated high-current discharge and regenerative braking. IC Role / Device Role / Timing Role: Detects cell imbalance-induced overvoltage during fast discharge recovery phases, initiating fuse blow before voltage rebound peaks. Use Value: Mitigates risk of cell venting during aggressive duty cycles, supporting EN 62133-2 mechanical and electrical safety testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar secondary overvoltage protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ29413PWR | Higher 4.50 V overvoltage threshold; identical pinout, timing, and quiescent current. | Suitable for battery chemistries with higher safe upper voltage limit (e.g., LiCoO₂ variants optimized for 4.5 V). | Select when system-level validation confirms 4.50 V is the required safety margin, not 4.45 V. |
| BQ29411PWR | Lower 4.40 V overvoltage threshold; same package, delay architecture, and temperature range. | Used where tighter voltage guardband is needed to protect aging cells or high-sensitivity cathode materials. | Choose when accelerated aging testing shows cell voltage excursions above 4.40 V indicate end-of-life or instability. |
Compared with BQ29412PWR, BQ29413PWR raises the trip point by 50 mV for enhanced headroom in high-voltage Li-ion variants, while BQ29411PWR lowers it by 50 mV to improve aging detection sensitivity-both retain identical delay programming, low-power operation, and TSSOP-8 footprint.
Availability
BQ29412PWR is available at Aetrix Electronics and suitable for portable instrumentation, professional power tools, and medical handheld devices requiring stable component supply with guaranteed long-term manufacturability and traceable sourcing.
Supply support for BQ29412PWR 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 experience in battery safety ICs.
The bq2941x product line was designed specifically for second-level hardware-based overvoltage protection in multi-cell Li-ion battery packs, emphasizing precision, ultra-low power, and robustness in harsh thermal and electrical environments.
FAQ
What is the exact overvoltage protection threshold of the BQ29412PWR?
The BQ29412PWR has a fixed, factory-trimmed overvoltage detection threshold of 4.45 V per cell, specified with ±25 mV accuracy at 25°C and ±50 mV over –20°C to 85°C. This value is unique to the BQ29412PWR within the bq2941x family and cannot be adjusted externally.
How does the BQ29412PWR implement programmable delay time?
The BQ29412PWR uses an internal 0.18 µA current source to charge an external capacitor connected to the CD pin; delay time equals (1.2 V × CDELAY) / 0.18 µA. A 0.22 µF capacitor yields 1–2 seconds delay, as verified in the BQ29412PWR datasheet's electrical characteristics table.
Can the BQ29412PWR be used in a 2-cell Li-ion configuration?
Yes - the BQ29412PWR supports 2S, 3S, and 4S configurations. For 2-cell use, VC1 and VC2 are shorted together and connected to the positive terminal, VC3 is shorted to VC1/VC2, VC4 connects to the negative terminal, and GND ties to system ground per TI Figure 5.
What is the maximum operating temperature range for the BQ29412PWR?
The BQ29412PWR is rated for continuous operation from –40°C to 110°C ambient temperature, validated per TI's recommended operating conditions. This range covers extreme environments such as automotive cabin storage, industrial tool housings, and outdoor medical equipment.
Does the BQ29412PWR require external passive components for basic operation?
Yes - the BQ29412PWR requires at minimum an external capacitor on the CD pin to set overvoltage delay time, plus optional RC filters on VC and VDD lines (e.g., 100 Ω + 0.01 µF) to suppress noise. No external resistors are needed for threshold setting, as it is internally fixed at 4.45 V.
BQ29412PWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Battery Protection
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 2 ~ 4
- Fault Protection:
- Over Voltage
- Interface:
- -
- Operating Temperature:
- -40°C ~ 110°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
BQ29412PWR FAQ
1.How can I place an order for BQ29412PWR through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ29412PWR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for BQ29412PWR reliable?
The price and inventory of BQ29412PWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ29412PWR is usually 5 days.
3.What payment methods are accepted for BQ29412PWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ29412PWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ29412PWR?
BQ29412PWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ29412PWR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for BQ29412PWR?
For technical support, including BQ29412PWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ29412PWR requirements.
6.How does Aetrix verify that BQ29412PWR is sourced from the original manufacturer or authorized distributors?
All BQ29412PWR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BQ29412PWR meets industry standards.
7.What is the process for return or replacement of BQ29412PWR?
All BQ29412PWR units undergo pre-shipment inspection (PSI). If there is an issue with BQ29412PWR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The BQ29412PWR part is unused and in its original packaging.
Return procedure for BQ29412PWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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