Technologies

Presented here is a power/data telemetry IC with a new data modulation scheme and simultaneous power transfer through a single inductive link. Data-driven synchronized single-cycle shorting of the secondary LC tank conserves reactive power while inducing an instantaneous voltage change at the primary side. Cyclic on-off keying time-encoded symbol mapping of the shorting cycle allowstransmission of two data bitsper four carrier cycles with simultaneous power transfer during non-shorting cycles. All timing control signals for rectification and data transmission are generated from a low-power clock recovery comparator and 22-phase 2xPLL.

The 1-mm ² 65-nm CMOS IC delivers up to 6.3-mW power and transmits 6.78-Mbps data with a BER of less than 5.9 × 10-7 over a single 1-cm 13.56-MHz inductive link.

Implanted medical devices (IMDs) employing bio-signal recording and transcutaneous transmission require a high data rate for the uplink while also being powered wirelessly e.g., intracranial multi-channel ECoG recording. Load Shift Keying (LSK), a widely used modulation scheme for uplink data telemetry, trades off power transfer and data-rate based on the inductive coil’s quality factorQ. High power transfer efficiency requires highQ, normally restricting the data rate. Data rates of 100-500 kbps with simultaneous power transfer have been achieved by LSK, and a few Mbps using multiple dedicated inductive links for data transfer and power transfer have also been realized. Further, using transient response from phase shifts by shorting the secondary LC tank for a half cycle achieves near 1-Mbps data rate with power transfer over single inductive link. However, this scheme loses energy whenever shorting the LC tank because of the subsequent reversal of LC resonance and the recovery time aftertransmitting one bitlimits the data rate. Approaches using higher RF bands require additional complexity in circuits and antenna structures.