This paper proposes a direct capacitance-to-digital converter (CDC) for biotelemetry applications. The proposed circuit is based on a charge redistribution technique using a capacitive sensor and a ranging capacitor array. The circuit does not require accurate reference voltages, so it is robust for fluctuation of supply voltage. Output-code range can be dynamically zoomed in arbitrary capacitance range of sensor output by using the ranging capacitor array. An 8-bit converter with an active area of 0.026mm 2 , consuming 0.9nJ per sample, is demonstrated. The proposed circuit maintains its performance even in the condition of 28% fluctuations in supply voltage. Measurement results of the readout circuit are also demonstrated, which shows that the proposed circuit can work well in the presence of large parasitic capacitances.

No abstract

This paper presents an ultra-low power 10-bit capacitance to digital converter. Full dynamic circuits realize zero-static power and ultra-low FoM of 290 fJ/conv. steps. It, for example, consumes only 3 nA at sampling frequency of 30 Hz. A differential architecture keeps the linearity error small up to the Nyquist frequency of sensor capacitance variation. Furthermore, internal clock signals are generated in self timed manner suitable for micro controller systems. The prototype was fabricated in 0.18 µm CMOS process and measured data fit with the real sensor characteristic precisely. These features are suitable for in-vivo medical systems or sensor-telemetry micro systems because of the ultra-low power and zero-static current operation with the high precision measure of pressure in asynchronous micro controller systems.

The NIRS-930 isochronous cyclotron has been used for various kinds of radiological and medical studies, such as development of new radiopharmaceuticals, basic research of radiobiological experiments, and study of particle detector for space. An ECR-IS has been installed in the axial injection system for extension of the research fields. New internal ion-source having two-slit geometry has been developed and successfully used in daily operation. A simple method of beam-energy measurement device was developed consisting of two capacitive-probes. A brief review of the developments and typical application of latest experiments in the various fields are described.

No abstract