Single-stage AC-to-DC switching converter that directly charges a battery requiring a multi-state charging profile

摘要

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.

主权项

1. A battery charger device for charging a rechargeable battery, the battery charger device comprising:
an output terminal adapted to be coupled to a battery assembly, wherein the rechargeable battery is a part of the battery assembly; a pair of AC supply voltage input terminals; a single-stage AC-to-DC switching converter circuit that receives a 110 volt AC RMS supply voltage from the pair of AC supply voltage input terminals and that supplies a charging current through the output terminal and to the battery, wherein the single-stage AC-to-DC converter comprises: a primary side circuit that comprises a pulse width modulator (PWM) integrated circuit and a primary winding of a transformer; and a secondary side circuit that comprises a secondary winding of the transformer, a current sense resistor, and a battery charger controller integrated circuit, wherein the battery charger controller integrated circuit detects a voltage on the output terminal and detects a current supplied to the rechargeable battery via the output terminal and sends a control signal to the PWM integrated circuit of the primary side circuit such that the rechargeable battery is charged in accordance with a multi-state battery charging profile, wherein the multi-state battery charging profile includes a constant current (CC) charging state and a constant voltage (CV) charging state, wherein a charging current supplied to the battery flows from the secondary winding, through the current sense resistor, through the output terminal, and into the battery without passing into the battery charger controller integrated circuit and without passing through any switching converter power stage and without passing through any linear regulator power stage, and wherein the battery charger controller integrated circuit comprises: a digital state machine circuit, wherein the digital state machine circuit is configured to implement a digital state machine, wherein the digital state machine is in a first state when the battery charger device is charging in the CC charging state, and wherein the digital state machine is in a second state when the battery charger device is charging in the CV charging state.