Title :
A 16-μA interface circuit for a capacitive flow sensor
Author :
Rodgers, Bertram ; Goenawan, Sofjan ; Yunus, Mohammad ; Kaneko, Yoshikazu ; Yoshiike, Junichi
Author_Institution :
Integrated Sensor Solutions, San Jose, CA, USA
fDate :
12/1/1998 12:00:00 AM
Abstract :
A micropower interface circuit is described for fluidic flow measurement in commercial gas meters. The application-specific integrated circuit converts dynamic capacitive-flow sensor readings from 1 to 150 Hz into digital pulses suitable for reading by the host microcontroller. The signal path is first-order ΔΣ modulation followed by a three-pole, one-zero infinite impulse response bandpass filter. Analog signal processing is fully differential switched capacitor, with amplifiers and dc current consuming blocks operating in weak inversion. Chip bias and oscillator frequency, and capacitive sensor offset and gain, are trimmed with on-chip EEPROM. Operating ranges are 2.5-3.6 V and from -10 to 65°C, with active Idd of 16 μA
Keywords :
IIR filters; analogue processing circuits; application specific integrated circuits; band-pass filters; capacitive sensors; flowmeters; low-power electronics; sigma-delta modulation; switched capacitor networks; ΔΣ modulation; -10 to 65 C; 1 to 150 Hz; 16 muA; 2.5 to 3.6 V; ASIC; EEPROM; IIR bandpass filter; analog signal processing; differential switched capacitor; digital pulse; dynamic capacitive flow sensor; fluidic flow measurement; gas meter; microcontroller; micropower interface circuit; Application specific integrated circuits; Capacitive sensors; Delta modulation; Fluid dynamics; Fluid flow measurement; IIR filters; Integrated circuit measurements; Microcontrollers; Pulse amplifiers; Pulse circuits;
Journal_Title :
Solid-State Circuits, IEEE Journal of
