Patent ID: 6522919
Filing Date: 2003-02-18
Classification: A61N

Abstract:
An iontophoresis system control circuit for use with an iontophoretic drug delivery device, the iontophoretic drug delivery device being placeable against the skin of a patient and having at least first and second electrodes, the control circuit comprising:a series pass regulator circuit, the series pass regulator circuit being responsive to a control voltage and controlling a desired drug delivery current in response thereto, the desired drug delivery current being flowable through the at least first and second electrodes and the skin of the patient, the series pass regulator circuit having a voltage Vs thereacross, the series pass regulator circuit being electrically coupled to the at least second electrode of the iontophoretic drug delivery device; a step-up DC-DC converter circuit, the step-up DC-DC converter circuit being electrically coupled to the at least first electrode and generating an output voltage V2 which is provided thereto, the impedance of at least one of the iontophoretic drug delivery device and the patient's skin and the desired drug delivery current flowing therethrough resulting in a voltage drop Vp across the at least first and second electrodes, wherein the voltage V2 is equal to the sum of the voltage Vp and the voltage Vs, the DC-DC converter circuit being responsive to the voltage Vp across the at least first and second electrodes and adjusting the output voltage V2 in response thereto so that the voltage Vs across the series pass regulator is substantially equal to the minimum voltage required to allow the series pass regulator to control the desired drug delivery current through the at least first and second electrodes and the patient's skin.