Abstract
This article presents a chip designed for wireless intra-cardiac monitoring systems. The design consists of a three-channel analog front-end, a pulse-width modulator featuring output-frequency offset and temperature calibration, and inductive data telemetry. By employing a resistance boosting technique in the instrumentation amplifier feedback, the pseudo-resistor exhibits lower non-linearity, leading to a total harmonic distortion of below 0.1%. Furthermore, the boosting technique enhances the feedback resistance, leading to a reduction in the size of the feedback capacitor and, consequently, the overall size. To make the modulator's output frequency resilient to temperature and process changes, coarse and fine-tuning algorithms are used. The front-end channel is capable of extracting the intra-cardiac signal with an effective number of bits of 8.9, while exhibiting an input-referred noise of less than 2.7 μ Vrms, and consuming 200 nW per channel. The front-end output is encoded by an ASK-PWM modulator, which drives an on-chip transmitter at 13.56 MHz. The proposed System-on-Chip (SoC) is fabricated in a 0.18 μ m standard CMOS technology and consumes 4.5 μW while occupying 1.125 mm2.
| Original language | English |
|---|---|
| Journal | IEEE Transactions on Biomedical Circuits and Systems |
| Volume | 17 |
| Issue | 5 |
| Pages (from-to) | 1097-1110 |
| Number of pages | 14 |
| ISSN | 1932-4545 |
| DOIs | |
| Publication status | Published - Oct 2023 |
Keywords
- Analog front-end (AFE)
- Electrocardiography
- electrocardiography (ECG)
- Frequency modulation
- implantable systems
- intra-cardiac signal
- Modulation
- Monitoring
- Receivers
- Transmitters
- Wireless communication
- wireless telemetry
- Telemetry
- Equipment Design
- Amplifiers, Electronic
- Monitoring, Physiologic
- Algorithms
- Wireless Technology
- Signal Processing, Computer-Assisted