Delta-sigma modulator with anti-windup circuit

A delta-sigma modulator, comprising:

• a loop filter circuit having a first input configured to receive an input signal, a second input configured to receive a feedback signal, and an output configured to generate a filtered signal;
• a clamping circuit having an input configured to receive the filtered signal and an output configured to generate a clamped filtered signal;
• a quantizer circuit configured to receive the filtered signal and generate a quantizer output signal;
• a first summation circuit configured to generate a dead zone signal from a difference between the filtered signal and the clamped filtered signal;
• and
• a second summation circuit configured to generate the feedback signal from a sum of the quantizer output signal and the dead zone signal.

A delta-sigma modulator, comprising:

• a loop filter circuit having a first input configured to receive an input signal, a second input configured to receive a feedback signal, and an output configured to generate a filtered signal;
• a quantizer circuit coupled to the output of the loop filter circuit and configured to generate a quantizer output signal;
• an anti-windup circuit configured to detect that the filtered signal is outside an input signal range of the quantizer circuit and generate a dead zone signal having a magnitude and sign corresponding to a difference between the filtered signal and the input signal range;
• and
• a summation circuit having a first input configured to receive the quantizer output signal, a second input configured to receive the dead zone signal, and an output configured to generate the feedback signal;
• wherein the anti-windup circuit comprises:
• a clamping circuit having maximum positive/negative clamp limits less than or equal to positive/negative limits of the input signal range of the quantizer circuit, said anti-windup circuit having an input configured to receive the filtered signal and an output configured to generate a clamped filtered signal for application to an input of the quantizer circuit;
• and
• a further summation circuit configured to generate the dead-zone signal from a difference between the filtered signal and the clamped filtered signal.

A delta-sigma modulator, comprising:

• a loop filter circuit having a first input configured to receive an input signal, a second input configured to receive a feedback signal, and an output configured to generate a filtered signal;
• a quantizer circuit coupled to the output of the loop filter circuit and configured to generate a quantizer output signal;
• an anti-windup circuit configured to detect that the filtered signal is outside an input signal range of the quantizer circuit and generate a dead zone signal having a magnitude and sign corresponding to a difference between the filtered signal and the input signal range;
• and
• a summation circuit having a first input configured to receive the quantizer output signal, a second input configured to receive the dead zone signal, and an output configured to generate the feedback signal;
• wherein the filtered signal is received at the input of the quantizer circuit and wherein the anti-windup circuit comprises:
• a clamping circuit having maximum positive/negative clamp limits less than or equal to positive/negative limits of the input signal range of the quantizer circuit, said anti-windup circuit having an input configured to receive the filtered signal and an output configured to generate a clamped filtered signal;
• and
• a further summation circuit configured to generate the dead-zone signal from a difference between the filtered signal and the clamped filtered signal.