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Texas Instruments BQ29312PW
- Part No.:
- BQ29312PW
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 24-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
BQ29312PW.pdf
- Description:
- IC BATT PROT LI-ION 2-4C 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,064
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Product details
Overview
BQ29312PW from Texas Instruments is a 2-, 3-, or 4-cell lithium-ion/polymer battery protection analog front-end (AFE) IC with integrated 3.3-V/25-mA LDO, I²C-compatible interface, and autonomous overcurrent/short-circuit protection. It monitors individual cell voltages (±1% error), provides thermistor bias (TOUT), supports cell balancing via external resistors, and delivers FET gate drive for CHG/DSG/ZVCHG in notebook PC and portable medical instrumentation.
For engineers reviewing the BQ29312PW datasheet, BQ29312PW pinout, BQ29312PW application, or BQ29312PW equivalent, this page delivers verified technical context-including programmable overload/short-circuit thresholds (50–205 mV / 100–475 mV), sleep/ship mode control, 60-µA typical supply current, and TSSOP-24 package compatibility-to support battery pack safety architecture validation and host controller integration.
Technical Context
The BQ29312PW implements dual-tier overcurrent protection: programmable overload detection (5–205 mV range, 5-mV steps, 10-mV hysteresis) with 1–31 ms blanking delay, and independent short-circuit detection for charge/discharge paths (100–475 mV, 25-mV steps, 50-mV hysteresis). Its I²C interface (0–100 kHz) enables real-time register access to STATUS, CONTROL, and FUNCTION CTL registers for dynamic FET control and fault clearing.
Cell voltage monitoring uses a precision scaling amplifier (K = 0.150 ±0.003 V/V) translating VCn–VC(n+1) into GND-referenced outputs (0–4.5 V), calibrated via internal reference (0.975 V) and register-controlled gain/offset correction. Thermistor drive (TOUT) delivers up to 1 mA with ≤100 Ω output impedance, while REG provides regulated 3.3 V (±2% line/load regulation) from 4.5–25 V input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 4.5 V to 25 V - supports direct connection to 2–4S Li-ion packs (8.4–16.8 V nominal) and auxiliary PACK+ input |
| Quiescent Current | 60 µA typical - enables ultra-low-power operation in battery-backed systems during standby |
| LDO Output | 3.3 V ±2%, 25 mA - powers external microcontrollers or sensors without secondary regulators |
| Cell Voltage Accuracy | ±1% error - ensures precise state-of-charge estimation when interfaced with gas gauge ICs like bq2084 |
| Overload Threshold | 50–205 mV programmable - sets discharge current limit (e.g., 2 A with 25 mΩ sense resistor) |
| Short-Circuit Response | 0–915 µs programmable delay - allows controlled shutdown during transient faults without nuisance tripping |
| I²C Clock Frequency | 0–100 kHz - compatible with standard-mode SMBus hosts and low-speed embedded controllers |
Pinout & Package
TSSOP-24 (PW) package: 7.8 mm × 4.4 mm, 0.65 mm pitch, exposed thermal pad (GND-connected), RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BAT | Primary power input | Diode-protected connection to battery stack anode; supplies internal circuitry when PACK is absent |
| PACK | Alternative power input | Connects to pack positive terminal; enables REG startup if BAT is disconnected |
| VC1–VC5 | Cell voltage sensing nodes | Measure differential voltages across 4 series cells (VC1–VC2, VC2–VC3, etc.) and enable cell balancing |
| SR1/SR2 | Current sense inputs | Differential pair for discharge current measurement; supports 10–30 mΩ sense resistors |
| CHG/DSG/ZVCHG | FET gate drivers | Push-pull outputs driving external N-channel MOSFETs; VGS clamp at 15 V prevents gate overstress |
| REG | LDO output | 3.3-V regulated supply for host MCU, sensors, or external logic; requires 4.7 µF ceramic capacitor |
| TOUT | Thermistor bias | Current source (≤1 mA) for NTC thermistors; enables temperature monitoring with <1% error |
| SLEEP | Power mode control | Pulled up to REG internally; grounding forces Sleep mode (20–40 µA current), floating enters Sleep via register |
| XALERT | Fault interrupt | Open-drain output asserting low on OL/SC fault, watchdog timeout, or SLEEP pin transition |
| SCLK/SDATA | I²C interface | Open-drain bidirectional lines with internal 10 kΩ pull-ups to REG; support standard-mode timing |
Key Features
| Feature | Design Value |
|---|---|
| Programmable Overload Protection | 50–205 mV threshold with 1–31 ms blanking delay - prevents false triggering during motor startup or pulse loads |
| Independent Short-Circuit Detection | Separate 100–475 mV thresholds for charge/discharge paths - enables asymmetric protection for charger vs. load faults |
| Cell Balancing Control | Register-selectable bypass path per cell with external resistor setting current - corrects voltage imbalance during charging without external switches |
| Multi-Power Mode Architecture | Normal/Sleep/Ship modes with 60 µA / 20–40 µA / 0.1–1.0 µA currents - extends shelf life and reduces parasitic drain |
| Integrated 3.3-V LDO | 25-mA output with ±2% regulation and 4.7 µF stability requirement - eliminates need for discrete regulator in space-constrained designs |
| Thermistor Bias with Low Impedance | ≤100 Ω output impedance on TOUT - minimizes voltage drop across PCB traces for accurate temperature readings |
Applications
| Notebook PC Battery Packs | Portable Medical Devices |
|---|---|
Use Scenario: 3-cell Li-ion pack powering clinical-grade handheld ultrasound with strict safety certification requirements. IC Role / Device Role / Timing Role: Primary protection AFE providing cell-level voltage monitoring, dual-tier overcurrent response, and thermistor-based thermal cutoff. Use Value: Enables compliance with IEC 62133 through autonomous short-circuit shutdown (<915 µs) and programmable overload hysteresis (7–13 mV). |
Use Scenario: Rechargeable defibrillator battery module requiring zero-volt charging capability and fail-safe ship mode. IC Role / Device Role / Timing Role: Safety-critical AFE managing pre-charge sequencing, 0 V charging enablement, and irreversible ship mode activation. Use Value: Supports UL 2054 compliance via latchable fault reporting (XALERT), ship current <1.0 µA, and ZVCHG FET drive for zero-volt recovery. |
| Industrial Handheld Test Equipment | High-Accuracy Portable Instrumentation |
Use Scenario: Ruggedized multimeter with 4S Li-polymer pack operating across –25°C to 85°C ambient. IC Role / Device Role / Timing Role: Temperature-compensated AFE delivering ±1% cell voltage accuracy and TOUT-driven NTC bias for thermal derating. Use Value: Maintains SOC accuracy over full temperature range using calibrated scaling factor (0.150 ±0.003) and internal reference trimming. |
Use Scenario: Precision gas analyzer with bq2084 gas gauge IC requiring high-fidelity cell voltage data. IC Role / Device Role / Timing Role: Analog front-end supplying individual cell voltages via CELL output with <1% error and I²C-accessible registers. Use Value: Enables <1% capacity prediction by feeding calibrated VCn–VC(n+1) data to host gas gauge, reducing calibration overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery protection AFE applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ29330PW | Higher integration: includes 5-V LDO, enhanced cell balancing algorithm, and extended temperature range (–40°C to 85°C) | Required for industrial applications needing wider temp range and higher drive capability (50 mA LDO) | Select BQ29330PW when system requires >25 mA LDO current or operation below –25°C |
| MP2617D | Monolithic solution with integrated charge FETs and buck charger; no separate CHG/DSG gate drivers | Used in compact single-board battery management where space prohibits discrete FETs | Choose MP2617D only for cost-sensitive consumer devices without need for external FET flexibility |
Compared with BQ29312PW, BQ29330PW offers broader temperature support and higher LDO current but at increased cost and pin count, while MP2617D sacrifices FET driver configurability for integration-making BQ29312PW optimal for modular, high-reliability 2–4S protection where discrete FET selection and register-level fault control are critical.
Availability
BQ29312PW is available at Aetrix Electronics and suitable for notebook PC battery packs, portable medical instrumentation, industrial handheld test equipment, and high-accuracy portable instrumentation requiring stable component supply and long-term lifecycle support.
Supply support for BQ29312PW 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 and embedded processing technologies, with decades of expertise in battery management solutions.
The BQ29312PW belongs to TI's battery protection AFE product line, designed specifically for high-safety, multi-cell lithium-ion/polymer applications demanding autonomous fault response, precision cell monitoring, and seamless host communication via I²C.
FAQ
What is the primary function of the BQ29312PW in a battery management system?
The BQ29312PW serves as a dedicated analog front-end for 2–4S lithium-ion/polymer battery protection, providing autonomous overvoltage, undervoltage, overcurrent, short-circuit, and thermal fault detection. It integrates cell voltage monitoring, FET gate drive control, a 3.3-V LDO, and I²C communication-enabling host microcontrollers to implement comprehensive safety and state-of-charge algorithms. The BQ29312PW does not include charging functionality but works alongside chargers like the bq247xx series.
How does the BQ29312PW support zero-volt charging functionality?
The BQ29312PW enables zero-volt charging through its ZVCHG FET driver pin, which controls an external MOSFET to allow pre-charge current into deeply discharged cells. When the battery voltage falls below the normal startup threshold, the ZVCHG path remains active under host control via the OUTPUT CTL register (bit 3), permitting safe trickle charging before enabling main CHG FET operation. This behavior is documented in the functional description section of the BQ29312PW datasheet.
Can the BQ29312PW be used with a 2-cell configuration, and how is it configured?
Yes, the BQ29312PW supports 2-cell configurations by shorting VC1 to VC2 and VC2 to VC3 per the device's functional description. In this setup, VC1–VC2 measures the total pack voltage, while VC3–VC4 and VC4–VC5 remain unused. The CELL_SEL register selects active cell pairs, and the protection thresholds (OL, SC) apply identically regardless of cell count. Configuration details are specified in Section 12 ("2-, 3-, or 4-Cell Configuration") of the BQ29312PW datasheet.
What is the role of the WDI pin on the BQ29312PW, and how does it affect system reliability?
The WDI (Watchdog Input) pin on the BQ29312PW provides a 32.768-kHz clock signal that synchronizes overload/short-circuit blanking delays and acts as a system watchdog timer. If the host fails to toggle WDI within 700 ms at startup or 100 µs during operation, the BQ29312PW disables CHG, DSG, and ZVCHG FETs to prevent unsafe conditions. This hardware-enforced fail-safe mechanism ensures BQ29312PW retains autonomy even if the host MCU locks up.
How is cell voltage accuracy achieved in the BQ29312PW, and what calibration steps are required?
The BQ29312PW achieves ±1% cell voltage accuracy using a precision scaling amplifier (K = 0.150 ±0.003) and internal 0.975-V reference. Calibration requires writing specific values to CAL0/CAL1 bits and measuring VREF and scaled outputs (VO(4–5), VOUTR) to compute actual K(ACT) and VOS(ACT), then applying corrections in firmware. Full procedure is detailed in Section 10 of the BQ29312PW datasheet, and calibration must be performed per cell for highest accuracy.
BQ29312PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Battery Protection
- Battery Chemistry:
- Lithium Ion/Polymer
- Number of Cells:
- 2 ~ 4
- Fault Protection:
- Over Current, Over/Under Voltage, Short Circuit
- Interface:
- I2C
- Operating Temperature:
- -25°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-TSSOP
BQ29312PW FAQ
1.How can I place an order for BQ29312PW through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ29312PW 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 BQ29312PW reliable?
The price and inventory of BQ29312PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ29312PW is usually 5 days.
3.What payment methods are accepted for BQ29312PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ29312PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ29312PW?
BQ29312PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ29312PW 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 BQ29312PW?
For technical support, including BQ29312PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ29312PW requirements.
6.How does Aetrix verify that BQ29312PW is sourced from the original manufacturer or authorized distributors?
All BQ29312PW 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 BQ29312PW meets industry standards.
7.What is the process for return or replacement of BQ29312PW?
All BQ29312PW units undergo pre-shipment inspection (PSI). If there is an issue with BQ29312PW, 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 BQ29312PW part is unused and in its original packaging.
Return procedure for BQ29312PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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