Sigma-Delta Modulators, Avago Technologies These miniature isolation amplifiers are using advanced Sigma-Delta Modulator technology for current sensing and voltage sensing in power converters. They provide accurate measurements of phase current and bus voltage. With built-in safety insulation and high Common Mode Rejection (CMR) performance, the Sigma-Delta Modulators offer an alternative to the traditional hall effect current sensor. Applications can be found in motor drives, power inverters and voltage signals in general isolation circuits.