US 11,990,917 B2
Incremental analog to digital converter incorporating noise shaping and residual error quantization
Omid Oliaei, Sunnyvale, CA (US); and Stephen Bart, West Newton, MA (US)
Assigned to INVENSENSE, INC., San Jose, CA (US)
Filed by INVENSENSE, INC., San Jose, CA (US)
Filed on Jun. 7, 2022, as Appl. No. 17/805,761.
Prior Publication US 2023/0396262 A1, Dec. 7, 2023
Int. Cl. H03M 1/06 (2006.01); H03M 1/00 (2006.01); H03M 1/12 (2006.01); H03M 1/46 (2006.01)
CPC H03M 1/462 (2013.01) [H03M 1/008 (2013.01); H03M 1/0604 (2013.01); H03M 1/0626 (2013.01); H03M 1/122 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A circuit, comprising:
an incremental analog to digital converter, comprising:
a loop filter that filters an analog input signal in response to receiving a reset signal, resulting in a filtered analog input signal; and
a successive approximation register (SAR) quantizer, coupled with the filtered analog input signal, that converts the filtered analog input signal to a first intermediate digitized output based on a first reference voltage, wherein the SAR quantizer comprises a feedback loop that shapes quantization noise generated by the SAR quantizer as a result of converting the filtered analog input signal, and wherein the first intermediate digitized output has a first resolution;
a digital to analog converter, coupled with the first intermediate digitized output, that converts the first intermediate digitized output to a converted analog signal;
a differential amplifier that subtracts the converted analog signal from the analog input signal, resulting in a residual analog input signal, wherein the SAR quantizer converts the residual analog input signal to a second intermediate digitized output based on a second reference voltage that is lower than the first reference voltage; and
a digital filter, coupled with the first intermediate digitized output, that generates a digitized output signal by digitally filtering the first intermediate digitized output, wherein the digitized output signal has a second resolution that is greater than the first resolution.