TI BQ2057CSNTR

The BQ2057 series advanced Li-ion and Li-pol linear charge management ICs are designed for cost-sensitive, compact portable electronics. They integrate high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge status indication, and AutoCompS charge rate compensation into a single 8-pin IC. MSOP, TSSOP, and SOIC package options are available to accommodate a wide range of end applications.

The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charging until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold V(min), the BQ2057 precharges at a low current to condition the battery. The conditioning charge rate is approximately 10% of the conditioning current. The conditioning current also minimizes heat dissipation in the external pass element during the initial stage of charging. After conditioning, the BQ2057 applies a constant current to the battery. An external sense resistor sets the current. The sense resistor can be placed on either the high side or low side of the battery with no additional components required. The constant current phase continues until the battery reaches the charge regulation voltage.

The BQ2057 then enters the constant voltage phase. Voltage regulation accuracy is better than ±1% over the full operating temperature and supply voltage range. The BQ2057 offers four fixed voltage versions for single-cell and dual-cell batteries: 4.1V, 4.2V, 8.2V, and 8.4V. Charging terminates when the current tapers to the charge termination threshold I(TERM). If the battery voltage falls below the V(RCH) threshold, the BQ2057 automatically restarts charging.

Designers can also use the AutoComp feature to reduce charge time. This proprietary technology enables safe, dynamic compensation of the battery pack's internal impedance during charging.

• Ideal for single-cell (4.1V or 4.2V) and dual-cell (8.2V or 8.4V) Li-Ion or Li-Polymer battery packs
• Minimal external components required
• 0.3V dropout voltage for minimized thermal dissipation
• Better than ±1% voltage regulation accuracy at preset voltage
• AutoCompM dynamically compensates battery pack internal impedance to reduce 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 recovers deeply discharged cells and minimizes thermal dissipation during initial charge phase
• Charge status output for one or two LEDs or host processor interface
• Automatic battery charging
• Charge termination at minimum current
• Automatic low-power sleep mode upon Vcc removal
• EVM available for rapid evaluation
• Package: 8-pin SOIC, 8-pin TSSOP, 8-pin MSOP

• Emergency call systems, telematics control units
• Aftermarket telematics
• Gaming and computer accessories
• Portable medical devices
• EPOS card readers