Capacitive data transmission over a galvanic isolation

A method comprising:

• generating an oscillating signal at a transmission frequency in a first voltage domain;
• receiving a first signal at the transmission frequency from a first capacitor arranged across a galvanic isolation barrier, wherein the galvanic isolation barrier separates the first voltage domain from a second voltage domain;
• receiving a second signal at the transmission frequency from a second capacitor arranged across the galvanic isolation barrier, wherein the first and second signal comprise a differential signal;
• filtering the first signal through a first passive RLC filter circuit of a common mode suppression circuit coupled between the first capacitor and a low-impedance node;
• and
• filtering the second signal through a second passive RLC filter circuit of the common mode suppression circuit coupled between the second capacitor and a low-impedance node,
• wherein a difference between the transmission frequency of the differential signal and a frequency associated with a peak in a transfer function of the first and second capacitors and the common mode suppression circuit is less than twenty percent,
• wherein filtering the first and second signals comprises suppressing a common mode signal communicated by the first and second capacitors, and
• wherein the first and second passive RLC filter circuits are arranged in the second voltage domain.

A system arranged to include a galvanic isolation barrier between a first voltage domain and a second voltage domain comprising:

• a first capacitor arranged across a galvanic isolation barrier;
• a second capacitor arranged across the galvanic isolation barrier, wherein the first and second capacitors are configured to communicate differential signals between the first and second domains;
• an oscillator configured to generate a first control signal and a second control signal at a transmission frequency, wherein the oscillator is arranged in the first voltage domain;
• a first driver stage configured to generate a first driver signal based on the first control signal and to deliver the first driver signal to a first side of the first capacitor;
• a second driver stage configured to generate a second driver signal based on the second control signal and to deliver the second driver signal to a first side of the second capacitor, wherein the first and second driver stages are arranged in the first voltage domain, wherein the differential signals comprise the first and second driver signals;
• a receiver circuit arranged in the second voltage domain;
• and
• a common mode suppression circuit arranged in the second voltage domain, the common mode suppression circuit comprising:
• a first passive RLC filter circuit coupled between a second side of the first capacitor, the receiver circuit, and the low-impedance node, wherein the second side of the first capacitor is different than the first side of the first capacitor, and wherein the first passive RLC filter circuit is configured to receive the first driver signal from the first capacitor;
• and
• a second passive RLC filter circuit coupled between the second capacitor, the receiver circuit, and the low-impedance node, wherein the second side of the second capacitor is different than the first side of the second capacitor, and wherein the second passive RLC filter circuit is configured to receive the second driver signal from the second capacitor,
• wherein a difference between the transmission frequency and a frequency associated with a peak in the transfer function of the common mode suppression circuit, the first capacitor and the second capacitor, for the differential signals, is less than twenty percent.