High resolution radiation sensor - has multiplexer connecting reference capacitor and measuring capacitor integrating sensor current signal to sensor output

摘要

The radiation sensor has a sensor element (T) providing a current proportional to the incident radiation, integrated via a capacitor (C1), coupled to the sensor element (T) in a switch (S1). A second switch (S2) couples a second capacitor (C2) to a reference current source (SQ), the capacitors (C1,C2) each connected at one side to the sensor output via a multiplexer (S5,S6,INV). A control device (ST) is coupled to the first capacitor and controls the 2 switches and the multiplexer, together with 2 further switches (S3,S4) across each capacitor for discharging the latter at the beginning of the measuring cycle. ADVANTAGE - High sensitivity and good dynamic range with small surface area requirement.