Patent ID: 7495420

Claim:
A voltage converter comprising: a switching regulator portion having a differential amplifier with inputs including a first reference signal and a first feedback signal, the switching regulator varying a duty cycle to substantially match the first feedback signal to the first reference signal, the switching regulator generating a first output voltage; a linear regulator portion controlling a series transistor to achieve a regulated second output voltage, a first terminal of the series transistor being coupled to the first output voltage of the switching regulator, a second terminal of the series transistor providing the regulated second output voltage; and a feedback circuit generating the first feedback signal signifying a conductance level of the series transistor, the first feedback signal being applied to the switching regulator to raise or lower the first output voltage of the switching regulator to achieve a particular differential voltage across the series transistor such that the conductance of the series transistor is maintained in steady state at a predetermined conductance level irrespective of a level of the regulated second output voltage wherein the series transistor is a bipolar transistor, the feedback circuit maintaining the bipolar transistor at a certain level in saturation.