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The BENCHMARQ bq 2057 series of advanced lithium-ion (Li-ion) and lithium-polymer (Li-POL) linear charge management integrated circuits are designed for cost-sensitive and compact portable electronics. They combine high precision current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge status indication, and automatic Comp charge rate compensation in a single 8-pin IC. MSOP, TSSOP and SOIC package options are available to suit a wide range of end applications.

The bq 2057 continuously measures battery temperature using an external thermistor. For safety, the bq 2057 inhibits charging until the battery temperature reaches a user-defined threshold. The bq 2057 then divides battery charging into three stages: conditioning, constant current, and constant voltage. If the battery voltage is below the low voltage threshold V(Min), the bq 2057 precharge uses a low current to condition the battery. The regulated charge rate is approximately 10% of the regulated current. Regulating the current also minimizes heat dissipation from the external channel components during the initial stages of charging. After adjustment, the bq 2057 applies a constant current to the battery. External inductors set the current. The inductors can be on both the high and low sides of the battery or without the need for additional components. The constant current phase continues until the battery reaches the charging regulation voltage.

The bq 2057 then begins the constant voltage phase. The voltage regulation accuracy is better than ±1% over the operating temperature and supply voltage range. For single and dual cells, the bq 2057 is available in four fixed voltage versions: 4.1V, 4.2V, 8.2V and 8.4V. The charge stops when the current reaches the charge termination threshold I (term). When the battery voltage falls below the V(Rch) threshold, the bq 2057 automatically restarts charging.

Measure the internal impedance of the battery pack while charging.

Ideal single-cell (4.1V or 4.2V) and dual-cell (8.2V or 8.4V) Li-Ion or Li-Ion packages require a small number of external components 0.3V decay voltage for minimum heat dissipation Better than ±1% voltage regulation accuracy , the preset voltage automatically Comp? Dynamic compensation of the battery pack. Internal impedance to reduce charge time Selectable temperature monitoring before and after battery charge Programmable charge current and high or low side current sensing Interface Automatic Battery Output - Charge Function Minimum Current Automatic Low Power Sleep Mode VCC is removed when charge is terminated, EVM can be used for quick evaluation Packages: 8-Pin SOIC, 8-Pin TSSOP, 8-Pin MSOP