Live demonstration: A batteryless CMOS ISFET array powered by body heat for real-time monitoring of bio-fluids
- Resource Type
- Conference
- Authors
- Douthwaite, Matthew; Georgiou, Pantelis
- Source
- 2017 IEEE Biomedical Circuits and Systems Conference (BioCAS) Biomedical Circuits and Systems Conference (BioCAS), 2017 IEEE. :1-1 Oct, 2017
- Subject
- Bioengineering
Components, Circuits, Devices and Systems
Sensors
Semiconductor device measurement
Generators
Integrated circuits
Real-time systems
Ring oscillators
Transmitters
- Language
We demonstrate a low-power CMOS ISFET array for pH sensing which is powered by body-heat alone. Each pixel in the 3-by-3 array contains an ISFET operating in weak-inversion that detects changes in pH as a current and the average of all the pixels then modulates a ring oscillator. The overall power of the sensing and processing ASIC is at most 6 μW. The ASIC also contains a ISM band bespoke transmitter which transmits measurements wirelessly. Power is supplied by a network of thermoelectric generators attached to an elastic strap worn on the forearm. Commercial power management ICs then create a stable 1.2 V supply for the sensing array. The ASIC is mounted on a test PCB with the management circuitry.