In one aspect the present invention provides an AC/DC or DC/DC adapter, comprising circuitry to generate a signal proportional to the maximum adapter current. In another aspect, the present invention provides a portable electronic device, comprising circuitry to receive a signal proportional to the maximum current supplied to the portable electronic device and a charger controller. Still another aspect of the present invention provides an adapter topology system, comprising an AC/DC or DC/DC adapter comprising circuitry to generate a signal proportional to the maximum adapter current; and a portable electronic device adapted to receive power from said adapter and to receive said signal proportional to the maximum adapter current.