FEATURES
• Over-Charge Protection
• Over-Discharge Protection
• Short Circuit Current Limiting
• Battery Open-Circuit Center Tap Protection
• Cell Voltage Balancing
• Undervoltage Lockout
• Individual Cell Voltage Monitoring
• Low Operating Current (30 μA) and Shutdown Current
(1 μA)
• Internal N-Channel MOSFET Driver
• High Noise Immunity
• Accurate (± 1.19 %) Over-Charge Voltage Detection
• Four Different Cell Types Covered
DESCRIPTION
The Si9730 monitors the charging and discharging of dualcell
lithium-ion battery packs (carbon or coke chemistry)
ensuring that battery capacity is fully utilized while ensuring
safe operation. The Si9730 provides protection against overcharge,
over-discharge, and short circuit conditions which
are hazardous to the battery and the environment.
Battery voltages of each individual cell are monitored at the
center-tap connection by an internal A/D converter through
the VC pin. If one or both of the cells is determined to be
overcharged, an internal cell balancing network "bleeds" off
current at 15 μA until both cells are charged to the same
maximum level. Depending on the condition of each cell, the
Si9730 will switch two external source-connected N-Channel
MOSFETs on or off to allow the cells to be charged or to provide
current to the load.
The Si9730 is available in an 8-pin SOIC package with an
operating temperature range of - 25 to 85 °C. The Si9730 is
available in both standard and lead (Pb)-free packages.