NOTEBOOK PC BATTERY CHARGE CONTROLLER AND SELECTOR WITH DPM

The BQ24700 BQ24701 is a highly integrated battery charge controller and selector tailored for the notebook and sub-notebook PC applications. The BQ24700 BQ24701 uses dynamic Power Management (DPM) to minimize battery charge time by maximizing use of available wall-adapter power. This is achieved by dynamically adjusting the battery charge current based on the total system (adapter) current. The BQ24700 BQ24701 uses a fixed frequency, pulse width Modulator (PWM) to accurately control battery charge current and voltage. Charge current limits CAN be programmed from a keyboard controller DAC or by external resistor dividers from the precision 5-V, 0.6%, externally bypassed Voltage Reference (VREF), supplied by the BQ24700 bq24701. The battery voltage limit CAN be programmed by using the internal 1.25-V, 0.5% precision reference, making it suitable for the critical charging demands of lithium-ion cells. Also, the BQ24700 BQ24701 provides an option to override the precision 1.25-V reference and drive the error Amplifier either directly from an external reference or from a resistor divider off the 5 V supplied by the integrated circuit. The selector function allows the manual selection of the system power source, battery or wall-adapter power. The BQ24700 supports battery-conditioning and battery-lean cycles through the ACSEL function. The ACSEL function allows manual selection of the battery or wall power as the main system power. It also provides autonomous switching to the remaining source (battery or ac power) should the selected system power source terminate (refer to Table 1 for the differences between the BQ24700 and the BQ24701 . The BQ24700 BQ24701 also provides an alarm function to indicate a depleted battery condition. The BQ24700 BQ24701 PWM Controller is ideally suited for operation in a buck converter for applications when the wall-adapter voltage is greater than the battery voltage. By Texas Instruments