Patent ID: 6930624

Claim:
An analog-to-digital converter system, comprising: a passive delta sigma converter stage comprising: a first filter receiving a converter stage analog input and a first analog feedback signal, the first filter being free of switching components and providing a first filtered analog signal according to the converter stage analog input and according to the first analog feedback signal, a quantizer coupled with the first filter, the quantizer providing a quantized output according to the first filtered analog signal, and a first digital-to-analog converter coupled with the first filter and with the quantizer, the first digital-to-analog converter providing the first analog feedback signal according to the quantized output; and an active gain stage coupled with the passive delta sigma converter stage, the active gain stage receiving a system analog input and providing the converter stage analog input according to the system analog input and the quantized output, wherein the active gain stage comprises: a second filter receiving the system analog input and a second analog feedback signal, the second filter being free of switching components; a second digital-to-analog converter coupled with the second filter and with the quantizer, the second digital-to-analog converter providing the second analog feedback signal according to the quantized output; and an amplifier coupled with the second filter; wherein the amplifier and the second filter provide the converter stage analog input according to a difference between the system analog input and the second analog feedback signal scaled by a gain factor, wherein the gain factor is about 25 or more.