Capacitive isolation circuitry with improved common mode detector

Abstract

An integrated circuit having voltage isolation capabilities comprising a first galvanically isolated area of the integrated circuit containing a first group of functional circuitry for processing a data stream. The first group of functional circuitry located in a substrate of the integrated circuit. Capacitive isolation circuitry located in conductive layers of the integrated circuit provides a high voltage isolation link between the first group of functional circuitry and a second group of functional circuitry connected to the integrated circuit through the capacitive isolation circuitry. The capacitive isolation circuitry includes a differential transmitter for transmitting data in a differential signal to the second group of functional circuitry via the capacitive isolation circuitry. A differential receiver receives data within the differential signal from the second group of functional circuitry via the capacitive isolation circuitry. A detector circuit within the differential receiver detects the received data. The detector circuit monitors the differential signal and generates a first logical output when a voltage generated responsive to the differential signal exceeds a programmable voltage threshold level and generates a second logical output when the voltage generated responsive to the differential signal falls below the programmable voltage threshold level.