An inductor based DC-DC converter of the present invention employs two
power switches such that only a fraction of inductor current flows
through sensing circuitry. The sensing circuitry itself is comprised of
sense transistors instead of resistors in order to further reduce power
dissipation and temperature variations. The sensing circuitry includes a
differential power supply that modifies a sense current employed as
feedback to one of its inputs. The sense transistors are selected and
configured such that the sense current is a relatively constant fraction
of the inductor current of the converter.