A mini-invasive multi-function biomedical pressure measurement system ASIC

A mini-invasive system ASIC for multiple bladder pressure measurement function is presented. Not only can the period of measurement be adjusted, the flexibility is also enhanced by using a tunable IA (instrumentation amplifier). Because the pressure inside the body cavity (i.e., bladder) usually does not vary drastically, a long-term mode is required to save the battery power for a reliable observation. Besides, the pressure dynamics in a cavity also could be examined in the continuous mode. The IA amplifies the signal sensed by the pressure sensor, which is then fed into the following ADC (analog-to-digital converter). Owing to the intrinsic 1-atm pressure (one atmospheric pressure) existing inside the body cavity and the various resolution requirement for the different applications, the input range of the IA must be able to be adjusted to keep the required linearity. The pressure range of the proposed system is found out to be 10.4~27.7 Psi with the maximum resolution of 8.42 × 10^-4 Psi, which is more than enough for most of pressure measurement applications.