Switched capacitor converter with tap-change capability

Abstract

A switched capacitor converter battery charging circuit can include an input that receives an input current, an output that delivers an integer multiple of the input current to a battery, a plurality of flying capacitor stages disposed between the input and output, and controller circuitry coupled to the flying capacitor stages that selectively enables or disables one or more of the flying capacitor stages to select the integer multiple responsive to a voltage supplied at the input. The flying capacitor stages can include a first plurality of flying capacitor stages forming a first phase of the converter and a second plurality of flying capacitor stages forming a second phase of the converter. The first and second phases can be operated in an interleaved manner to reduce current or voltage ripple. The converter can include three flying capacitor stages, providing for selection of integer multiples of 4×, 3×, 2×, or 1×.