The HY2122-AB1B is a high-precision protection IC specifically designed for 2-cell series (2S) Lithium Iron Phosphate (LiFePO4) battery packs. Housed in a SOT-23-6 package, it monitors the voltage of each cell and the discharge current to protect against overcharge, over-discharge, and over-current conditions.

Specifications

• Battery Type: 2-Cell LiFePO4 (Series)
• Overcharge Detection Voltage (Vcu): 3.650V ± 0.025V
• Overcharge Release Voltage (Vcr): 3.450V ± 0.050V
• Over-discharge Detection Voltage (Vdl): 2.000V ± 0.080V
• Over-discharge Release Voltage (Vdr): 2.500V ± 0.100V
• Discharge Over-current Detection (Vdip): 200mV ± 30mV
• Short Circuit Detection Voltage (Vsip): 1.0V (Fixed)
• Operating Temperature: -40°C to +85°C
• Package: SOT-23-6

Features

• High-Accuracy Detection: Built-in high-precision voltage detection and delay circuits ensure safety without requiring external capacitors.
• Auto Over-discharge Recovery: The "AB1B" variant features an automatic recovery function, allowing the battery to resume normal operation once the voltage rises back to the release level.
• 0V Battery Charging: Includes a "0V Battery Charge" function, allowing the charging of cells that have been deeply discharged (available in this model).
• Low Power Consumption:
  • Operation Mode: 9uA (at Vdd = 6.4V)
  • Standby Mode: 0.1uA (at Vdd = 3.4V)
• High Withstand Voltage: The charger connection pins (CS and OC) are designed to withstand up to 33.

Common Applications

• LiFePO4 Battery Packs: Specifically tuned for the lower nominal voltage of LiFePO4 chemistry (3.2V nominal).
• Portable Power Tools: Managing 2S battery configurations for 6.4V systems.
• Solar Energy Storage: Small-scale 2-cell LiFePO4 storage solutions for solar lighting.
• Electric Toys: Reliable safety monitoring for high-drain hobbyist battery packs.

Usage Tips

• Chemistry Match: Ensure you are using LiFePO4 cells. If you use standard Li-ion (4.2V max), the 3.65V cut-off of this IC will prevent the batteries from ever reaching full charge.
• MOSFET Pairing: Always pair with appropriate N-channel MOSFETs capable of handling your load current.
• Layout: Place the decoupling capacitor between VDD and VSS as close to the IC pins as possible to avoid false triggers due to noise

Datasheet