Overview
The BQ29209DRBT is a secondary overvoltage protection IC designed by Texas Instruments for 2-series cell lithium-ion battery packs. This device integrates a high-accuracy precision overvoltage detection circuit and automatic cell imbalance correction. It ensures that each cell in the battery pack operates within safe voltage limits, preventing overvoltage conditions that could damage the cells. The BQ29209DRBT is particularly useful in applications requiring reliable and efficient battery management.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Package Type | VSON-8 (DRB) | |
| Pins | 8 | |
| Operating Temperature Range | -40°C to 110°C | °C |
| Overvoltage Detection Voltage | 4.30 V | V |
| Overvoltage Detection Hysteresis | 200 - 400 mV | mV |
| Overvoltage Delay Time Scale Factor | 9 s/µF (typical) | s/µF |
| Cell Balancing Current (Internal) | Up to 15 mA | mA |
| Low Power Consumption | < 3 µA (typical, VCELL(ALL) < VPROTECT) | µA |
| Battery Chemistry | Lithium Ion | |
| Number of Cells | 2 |
Key Features
- 2-Series Cell Secondary Protection
- Automatic Cell Imbalance Correction with External Enable Control
- ±30-mV Enable, 0-mV Disable Thresholds for Cell Balancing
- External Capacitor-Controlled Delay Timer
- External Resistor-Controlled Cell Balance Current
- Low Power Consumption (ICC < 3 µA typical, VCELL(ALL) < VPROTECT)
- Internal Cell Balancing Handles Current up to 15 mA
- External Cell Balancing Mode Supported
- High-Accuracy Overvoltage Protection: ±25 mV with TA = 0°C to 60°C
- Fixed Overvoltage Protection Thresholds: 4.30 V, 4.35 V
- Small 8L DRB Package
Applications
- Second-level protection in Li-Ion battery packs
- Netbook computers
- Power tools
- Portable equipment and instrumentation
- Battery backup systems
Q & A
- What is the primary function of the BQ29209DRBT?
The primary function of the BQ29209DRBT is to provide secondary overvoltage protection and automatic cell imbalance correction for 2-series cell lithium-ion battery packs.
- What is the overvoltage detection voltage for the BQ29209DRBT?
The overvoltage detection voltage for the BQ29209DRBT is 4.30 V.
- How does the cell balancing feature work?
The cell balancing feature starts when the cell voltages are different by nominally 30 mV or more and stops when the difference is nominally 0 mV. It is enabled and disabled by the CB_EN pin.
- What is the typical low power consumption of the BQ29209DRBT?
The typical low power consumption is less than 3 µA when VCELL(ALL) is less than VPROTECT.
- What is the operating temperature range of the BQ29209DRBT?
The operating temperature range is -40°C to 110°C.
- How is the delay time for overvoltage protection controlled?
The delay time is controlled by an external capacitor connected to the CD pin, with a scale factor of nominally 9 s/µF.
- Can the BQ29209DRBT support external cell balancing current?
Yes, the BQ29209DRBT can be configured to support higher external cell balancing current via external circuitry.
- What package type does the BQ29209DRBT come in?
The BQ29209DRBT comes in an 8-pin VSON (DRB) package.
- What are some typical applications of the BQ29209DRBT?
Typical applications include netbook computers, power tools, portable equipment and instrumentation, and battery backup systems.
- How accurate is the overvoltage protection of the BQ29209DRBT?
The overvoltage protection has an accuracy of ±25 mV with TA = 0°C to 60°C.
