A current mirror divides an input source voltage dynamically, to provide a controlled voltage that corresponds to an output load voltage. The correspondence between this controlled voltage and the output load voltage determines the correspondence between the output current and the input current. By dynamically adjusting the controlled voltage, the correspondence to the output load voltage can be maintained to very low voltage. Preferably, the output load voltage is also dynamically divided to provide a comparison voltage for comparing to the controlled voltage when the output load voltage is high, thereby providing the appropriate output current at high voltage levels. The combination of these two techniques provides a wide output voltage compliance, and a high output impedance.