针对 2 节、3 节或 4 节锂离子和锂聚合物电池的 2 级过压保护（第 2 级保护）
| Function | Protection |
| Number of series cells (Min) | 2, 3, 4 |
| Number of series cells (Max) | 3, 4 |
| Features | Overvoltage, Single pin output drive |
| Typical operating current (Typ) (uA) | 2 |
| Rating | Catalog |
| Vin (Max) (V) | 25.3 |
- 2-, 3-, or 4-Cell Secondary Protection
- Low Power Consumption ICC < 2 μA [VCELL(ALL)
- High Accuracy Over Sense Voltage:
- bq29400: 4.35 V ±25 mV
- bq29400A: 4.40 V ±25 mV
- bq29401: 4.45 V ±25 mV
- bq29405: 4.65 V ±25 mV
- Prefixed Protection Threshold Voltage
- Programmable Delay Time
- High Power Supply Ripple Rejection
- Stable During Pulse Charge Operation
- APPLICATIONS
- 2nd Level Protection in Lion Battery Packs in
- Notebook PCs
- Portable Instrumentation
- Medical and Test Equipment
- 2nd Level Protection in Lion Battery Packs in
The bq29400, bq29400A, bq29401, and bq29405 are BiCMOS secondary protection ICs for 2-, 3-, or 4-cell Lithium-Ion battery packs that incorporate a high-accuracy precision over voltage detection circuit. They include a programmable delay circuit for over voltage detection time.
Each cell in a multiple cell pack is compared to an internal reference voltage. If one cell reaches an overvoltage condition, the protection sequence begins. The bq2940x device starts charging an external capacitor through the CD pin. When the CD pin voltage reaches 1.2 V, the OUT pin changes from a low level to a high level.
