1. A device, comprising:a DC input configured to receive a DC input voltage;
a DC output configured to deliver a DC output voltage;
a current sensor for measuring a DC input current and generating a current signal related to the DC input current;
a comparator circuit for comparing a reference signal derived from a DC output voltage with the current signal to generate a comparison signal;
a control circuit coupled to the comparator circuit, and responsive to the comparison signal, the control circuit is configured to regulate an output current to be directly proportional to a DC input voltage and independent of the DC output voltage.