Abstract: A multi-state battery charger includes a single-stage AC-to-DC switching converter, where the single-stage converter receives an AC supply voltage and directly charges a rechargeable battery without there being any intervening second power stage. A novel battery charger controller integrated circuit in the converter's secondary side detects profile selection resistor values, monitors battery voltage, monitors charging current, monitors battery temperature, controls a protection transistor, and sends a control signal back to a PWM in the primary side. The controller includes a flexible preprogrammed digital state machine circuit that is configured to control the converter from charging state to charging state so that the battery is charged in accordance with a selected one of multiple preprogrammed different multi-state battery charging profiles, where at least one of the profiles has at least one CC (constant current) state and one CV (constant voltage) state.

Abstract: A multi-state battery charger includes a single-stage AC-to-DC switching converter, where the single-stage converter receives an AC supply voltage and directly charges a rechargeable battery without there being any intervening second power stage. A novel battery charger controller integrated circuit in the converter's secondary side detects profile selection resistor values, monitors battery voltage, monitors charging current, monitors battery temperature, controls a protection transistor, and sends a control signal back to a PWM in the primary side. The controller includes a flexible preprogrammed digital state machine circuit that is configured to control the converter from charging state to charging state so that the battery is charged in accordance with a selected one of multiple preprogrammed different multi-state battery charging profiles, where at least one of the profiles has at least one CC (constant current) state and one CV (constant voltage) state.