PT1505 Datasheet | PowTech

DESCRIPTION The PT1505 is an integrated power management unit and white LED driver for small handheld portable applications. It contains a single-cell Lithium Ion battery charger, a synchronous step-down DC-DC converter, 2 Low Dropout Regulators and a step-up DC-DC converter designed for driving up to 8 white LEDs in series. It allows charging from both wall adapter and USB port. When charging from wall adapter, the PT1505 increases the charging current automatically. The battery charger is a highly integrated charging management device targeted at space limited portable applications. It offers an integrated MOSFET and current sensor, reverse blocking protection, high accuracy current and voltage regulation, and charge termination. It charges a battery in three phases: trickle charging, constant current and constant voltage. No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. The thermal feedback regulates the charging current to limit the chip temperature during high power operation or high ambient temperature to maximize the charge rate without risk of overheating. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The PT1502 automatically terminates the charge cycle when the charge current drops to 1/10 the programmed value after the final float voltage is reached. The PT1502 automatically re-starts the charge if the battery voltage falls below an internal threshold. The step-down converter is a high efficiency monolithic current mode synchronous buck regulator with a constant operation frequency. A main switch and a synchronous switch are integrated in PT1502, the device has high efficiency and no external Schottky diode needed. 100% duty cycle provides low dropout operation, extending battery life in portable systems. Automatic burst mode operation at light loads provides high efficiency. Internal 1.5MHz switching frequency allowing the...