Abstract: Embodiments of the present invention include circuits and methods for sensing resistance. In one embodiment the present invention includes a method comprising detecting a voltage at an input of a regulator received from a power adapter, determining a maximum current capability of the power adapter, and charging a battery coupled to an output of the regulator using said detected voltage and said maximum current as inputs to said regulator. In one embodiment, the detected voltage is used to configure a voltage used to determine if or when a voltage received from a power adapter drops below some threshold.

Abstract: Embodiments of the present invention include techniques for charging a battery using a switching regulator. Some embodiments include programmable switching battery chargers that can be configured using digital techniques. Other embodiments include switching battery chargers that modify the battery current based on sensed circuit conditions such as battery voltage or input current to the switching regulator. In one embodiment, the present invention includes a USB battery charger.