Active discharge of a coupling capacitor in an implantable medical device

Abstract

An active discharge circuit for use within an implantable medical device, such as a pacemaker, rapidly discharges a coupling capacitor connected between a therapy circuit and body tissue. The active discharge circuit has a switching device, a charge transfer capacitor, and a clock. The clock is coupled to a control input of the switching device and provides a clock signal thereto. In response to the clock signal, the switching device sequentially and repeatedly couples the charge transfer capacitor to a discharge voltage supply so that charge transfers therebetween, and then couples the charge transfer capacitor to the coupling capacitor so that charge transfers therebetween. As the switch oscillates in response to the clock signal, the coupling capacitor is actively discharged.