TI BQ2057WTSTR

The BENCHMARQ bq2057 series of advanced lithium-ion (Li-Ion) and lithium-polymer (Li-Pol) linear charge management ICs are designed for cost-sensitive and compact portable electronic devices. They integrate high-precision current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge status indication, and AutoComp charge rate compensation in an 8-pin IC. MSOP, TSSOP, and SOIC package options are available to suit a wide range of end applications. The bq2057 uses an external thermistor to continuously measure the battery temperature. For safety, the bq2057 prohibits charging until the battery temperature is within the user-defined threshold range. Then, the bq2057 charges the battery in three stages: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold V(min), the bq2057 will use a low current for pre-charging to condition the battery. The conditioning charge rate is approximately 10% of the regulated current. The conditioning current also minimizes the heat dissipation of external shunt components during the initial charging phase. After conditioning, the bq2057 applies a constant current to the battery. An external sense resistor sets the current. The sense resistor can be located at the high side or low side of the battery without additional components. The constant current stage continues until the battery reaches the charge regulation voltage. Then, the bq2057 starts the constant voltage stage. The voltage regulation accuracy is better than ±1% over the operating temperature and supply voltage range. For single-cell and dual-cell batteries, the bq2057 offers four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charging stops when the current decreases to the charge termination threshold I(TERM). If the battery voltage drops below the V(RCH) threshold, the bq2057 automatically restarts charging. Designers can also use the AutoComp function to reduce the charging time. This proprietary technology allows for safe and dynamic compensation of the internal impedance of the battery pack during charging.

• Single-cell (4.1V or 4.2V) and dual-cell (8.2V or 8.4V) Li-Ion or Li-Polymer battery pack support
• Minimal external components required
• 0.3V dropout voltage for reduced heat dissipation
• Voltage regulation accuracy better than ±1% at preset voltage
• AutoComp dynamic compensation of battery pack internal impedance for reduced charge time
• Optional cell temperature monitoring before and during charging
• Integrated voltage and current regulation with programmable charge current and high-side or low-side current sensing
• Integrated cell conditioning for recovering deeply discharged cells and reducing heat dissipation during initial charge phase
• Charge status output for single or dual LED or host processor interface
• Automatic battery recharge
• Charge termination via minimum current
• Automatic low-power sleep mode when VCC is removed
• EVM available for rapid evaluation
• Package: 8-pin SOIC, 8-pin TSSOP, 8-pin MSOP

• Portable electronic devices
• Single-cell or dual-cell Li-ion or LiPo battery charge management