Modelling of a Capacitance-to-Period Converter Dedicated to Capacitive Sensors

Philippe Menini (1) , Philippe Dondon (2) , G. Blasquez (1) , Patrick Pons (1)

1 LAAS - Laboratoire d'analyse et d'architecture des systèmes
2 IMS - Laboratoire de l'intégration, du matériau au système

This paper analyses a BiCMOS integrated circuit for interfacing capacitive sensors. A demonstrator has been implemented to evaluate its actual behaviour. This converter is based on the charge and the discharge of a capacitor with a constant current. A simple analytical model as first-order theory has been compared with PSPICE simulations and experimental data. Significant errors reveal the influence of leakage currents, stray capacitors and interference due to clock feedthrough and charge injection phenomena. Analytical and electrical models have been extended to include these parasitic parameters and simulate properly their thermal behaviour. Experimental data show close agreement between these models and practice.

Mots clés: Capacitive pressure sensors; BiCMOS converter; PSPICE; Modelling

Domaines: Electronique

Philippe Menini, Philippe Dondon, G. Blasquez, Patrick Pons. Modelling of a Capacitance-to-Period Converter Dedicated to Capacitive Sensors. EUROSENSORS XIII, Sep 1999, LA HAYE, Netherlands. pp.279. ⟨hal-00350358⟩