Abstract
An ultra-low power fully dynamic capacitance-to-digital converter (CDC) that exploits a novel charge reuse technique is proposed. The CDC includes a capacitive bridge as the sensing frontend and an asynchronous SAR ADC for signal digitization. Passive charge sharing between the frontend and ADC is used to enable a fully dynamic operation. Instead of resetting the capacitive bridge (with large sensing and reference capacitors) for each measurement, the charge is maintained and reused over many measurements to save energy. A power gating technique is employed to reduce the stand-by power. As a result, a FoM as low as 4.3fJ/conv-step is achieved for the CDC, which is >3x better than the state-of-the-art. Furthermore, it supports an inherent scaling of power vs. speed with a minimum power of only 44pW and a compact chip area of 6440μm2.
Original language | English |
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Article number | 9249050 |
Pages (from-to) | 514-517 |
Number of pages | 4 |
Journal | IEEE Solid-State Circuits Letters |
Volume | 3 |
DOIs | |
Publication status | Published - 5 Nov 2020 |
Keywords
- Capacitance-to-digital converter (CDC)
- charge reuse
- dynamic
- internet-of-things (IoT)
- power-gating.