论文信息 - A switched-capacitor interface for capacitive sensors based on relaxation oscillators

A switched-capacitor interface for capacitive sensors based on relaxation oscillators

A switched-capacitor (SC) interface for capacitive sensors based on a modified Martin's relaxation oscillator is proposed. The output signal is the duty-cycle of a pulse-width modulated square-wave voltage or a binary-coded digital signal which is directly related to the capacitance ratio of an unknown capacitance and reference capacitance. The circuit can be implemented in a monolithic IC form using CMOS technology. It requires a relatively small device count integrable onto a small chip area and its suited particularly for the on-chip interface circuitry for microprocessors. >

Andrzej Cichocki | Rolf Unbehauen

[1] Andrzej Cichocki,et al. MOS Switched-Capacitor and Continuous-Time Integrated Circuits and Systems: Analysis and Design , 1989 .

[2] Andrzej Cichocki,et al. Appllication of switched-capacitor self-oscillating circuits to the conversion of RLC parameters into a frequency or digital signal , 1990 .

[3] K. Martin. A voltage-controlled switched-capacitor relaxation oscillator , 1981, IEEE Journal of Solid-State Circuits.

[4] R. G. Green,et al. A high frequency stray-immune capacitance transducer based on the charge transfer principle , 1988 .

[5] Kenzo Watanabe,et al. A switched-capacitor interface for capacitive sensors with wide dynamic range , 1989 .

[6] Kenzo Watanabe,et al. A switched-capacitor charge-balancing analog-to-digital converter and its application to capacitance measurement , 1987, IEEE Transactions on Instrumentation and Measurement.