Texas Instruments Incorporated
OVERLOAD RECOVERY METHOD IN SIGMA DELTA MODULATORS

Abstract:

A delta sigma modulator includes two adders, an integrator stage, a reconfigurable local resonator, an analog-to-digital converter (ADC), and a digital-to-analog converter (DAC). A first adder receives an analog input signal at an additive input, and the integrator stage receives an output from the first adder and generates an integrated signal. The reconfigurable local resonator receives the integrated signal and generates a resonator output signal. A second adder receives the resonator output signal, the integrated signal, and the input signal. The ADC receives an output from the second adder and generates a digital output signal which can be provided to other circuits. The DAC receives the digital output signal, and generates and provides a feedback signal to a subtractive input of the first adder. The reconfigurable local resonator acts as a resonator, but reconfigures to act as a low pass filter in response to overload conditions.