A medical imaging system includes an imaging device for inserting into a lumen of a catheter. The imaging device includes an ultrasound transducer and bias circuitry electrically coupled to the transducer for biasing the transducer. At least one communication line is coupled to both the ultrasound transducer and the bias circuitry and extends to a proximal end of the catheter. The at least one communication line transmits a transducer drive signal to the transducer and a charge signal to the bias circuitry. At least one inductive coupler is in communication with the at least one communication line. The transducer drive signal and the charge signal are both AC signals. The transducer drive signal has a transducer-drive-signal frequency and the charge signal has a charge-signal frequency that is different than the transducer-drive-signal frequency.