Converter Facilitates Level Sensing in Diagnostic Systems
Jim Scarlett · 2014
CDC Technology At a basic level, Σ-Δ ADCs make use of a simple charge-balancing circuit, with a known reference voltage and an unknown input voltage applied across fixed on-chip input capacitors. Charge balancing determines the unknown input voltage. Σ-Δ-based CDCs differ in that the unknown value is the input capacitor. A known excitation voltage is applied to the input, and charge balancing detects changes in the unknown capacitor, as shown in Figure 1. The CDC retains the resolution and linearity of the ADC.