US 11,870,453 B2
Circuits and methods for a noise shaping analog to digital converter
Martin Kinyua, Cedar Park, TX (US); and Eric Soenen, Cedar Park, TX (US)
Assigned to Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed on Apr. 12, 2022, as Appl. No. 17/718,467.
Claims priority of provisional application 63/281,790, filed on Nov. 22, 2021.
Prior Publication US 2023/0179214 A1, Jun. 8, 2023
Int. Cl. H03M 1/08 (2006.01)
CPC H03M 1/0854 (2013.01) 20 Claims
OG exemplary drawing
 
1. An analog-to-digital conversion (ADC) circuit, comprising:
a first quantization stage configured to receive an analog input signal and sample the analog input signal to generate a first digital signal, the first quantization stage further configured to filter the first digital signal with a first noise-shaping transfer function to generate a first noise-shaped digital output and to generate a quantization error signal based on a comparison of the analog input signal and the first noise-shaped digital output;
a voltage controlled oscillator (VCO)-based second quantization stage configured to receive the quantization error signal and sample the quantization error signal to generate a second digital signal, the VOC-based second quantization stage further configured to filter the second digital signal with a second noise-shaping transfer function to generate a second noise-shaped digital output;
a first digital filter configured to filter the first noise-shaped digital output with an equivalent signal transfer function of the VCO-based second quantization stage to generate a first stage digital output;
a second digital filter configured to filter the second noise-shaped digital output with the first noise-shaping transfer function to generate a second stage digital output with second order noise-shaping characteristics; and
a combination circuit that combines the first stage digital output and the second stage digital output to generate a digital ADC output signal with second order noise shaping characteristics.