Pulse delay modulation (PDM) a new wideband data transmission method to implantable medical devices in presence of a power link

This paper introduces a new technique, called pulse delay modulation (PDM), for wideband data transmission across inductive links along with the power carrier. It consumes small power, provides robustness against strong power carrier interference, and does not affect the power transfer efficiency (PTE). In PDM, a pattern of narrow pulses are transmitted at precise time delays for each data bit through an inductive link to initiate a short oscillatory pattern across the receiver (Rx) data coil. This oscillation shifts the zero-crossings of the undesired sinusoidal power carrier interference on the Rx data coil, resulting in a phase shift between the Rx power and data signals, from which the data bit stream can be recovered. We describe the PDM theoretical foundation and demonstrate its operation via post-layout simulation of a PDM transceiver, designed in a 0.35-μm standard CMOS process, using a realistic inductive link model. The PDM transceiver is expected to achieve a data rate of 13.56 Mbps at 1 cm data coils separation with up to 2 mm misalignment while delivering >;250 mW through an orthogonal power transmission link to an implantable medical device.