Bio-implantable systems have developed to possess a wireless power and data transmission structure. As a result, many wireless bio-implantable systems use a power regulator and ASK demodulator. For the design of ASK demodulator, higher modulation rate results in higher data transmission efficiency, and a lower modulation index results in higher power transmission efficiency. This study presents a receiver circuit that contains a high efficient ASK demodulator structure with an on-chip power regulator for biomedical implantable systems. This design has been fabricated and tested in TSMC 0.18- m 1P6M CMOS technology.
Measurement results show that the proposed ASK demodulator structure has a minimum modulation index as low as 4.05% and a maximum 50% modulation rate at 2MHz carrier frequency. The modulation index is also tunable for different applications. The power regulator provides a stable 1.8V for chip power.