Methods and apparatus for a delta sigma ADC with parallel-connected integrators
Various embodiments of the present technology may comprise a method and device for a delta-sigma ADC. The method and device may comprise receiving an input signal to at least two parallel-connected first-stage integrators and corresponding feedback DACs, and simultaneously integrating the input signal by each of the first-stage integrators. The method and device may further comprise a second stage integrator connected in series with the first-stage integrators, a quantizer, and digital to analog converters, coupled between the output of the quantizer and the inputs of the first-stage integrators.
1. A delta sigma modulator comprising:
at least two first-stage integrators connected in parallel, each integrator comprising:
at least one of each of a capacitor, a switching device, and an operational amplifier;
a second-stage integrator connected in series with the first-stage integrators;
a quantizer connected in series with the second-stage integrator; and
at least two digital-to-analog converters, wherein a first digital-to-analog converter is coupled between an output of the quantizer and an input of a first first-stage integrator, and a second digital-to-analog converter is coupled between the output of the quantizer and an input of a second first-stage integrator.
2. The delta sigma modulator of claim 1 , wherein each of the integrators comprises a fully differential topology.
3. The delta sigma modulator of claim 1 , wherein at least one of the digital-to-analog converters is a single-bit converter and the quantizer is a single-bit quantizer.
4. The delta sigma modulator of claim 1 , wherein the digital-to-analog converter is a multi-bit converter and the quantizer is a multi-bit quantizer.
5. The delta sigma modulator of claim 1 , wherein at least one of the at least two first-stage integrators is configured as a negative phase integrator.
6. The delta sigma modulator of claim 1 , wherein each of the first-stage integrators is configured as a positive phase integrator.
7. The delta sigma modulator of claim 1 , wherein the second-stage integrator comprises an addition function.
8. The delta-sigma modulator of claim 1 , wherein the capacitors of the first-stage integrators have capacitance values that are substantially equal to each other, the switching devices of the first-stage integrators are substantially equal in size, and the op-amps of the first-stage integrators have substantially equal topology and size.
9. The delta-sigma modulator of claim 1 , wherein each of the digital-to-analog converters comprises a capacitor having a capacitance value, and wherein the capacitance value of the first digital-to-analog converter is substantially equal to the capacitance value of the second digital-to-analog converter.
10. A method for operating a delta sigma modulator with an increased signal-to-noise ratio comprising:
receiving an input signal by at least two first-stage integrators connected in parallel, each first-stage integrator comprising:
at least one of each of a capacitor, a switching device, and an operational amplifier;
simultaneously integrating the input signal by each of the first-stage integrators;
transmitting a signal to a second-stage integrator connected in series with the first-stage integrators; and
quantizing the signal to produce a digital output.
11. The method of claim 10 , wherein at least one of the first-stage integrators is configured as a negative phase integrator.
12. The method of claim 10 , wherein each of the first-stage integrators is configured as a positive phase integrator.
13. A system comprising:
a micro electro-mechanical device;
a delta-sigma modulator coupled to the micro electro-mechanical device comprising:
at least first and second first-stage integrators connected in parallel, each integrator comprising:
at least one of each of a capacitor, a switching device, and an operational amplifier;
a second-stage integrator connected in series with the first-stage integrators;
a quantizer connected in series with the second-stage integrator;
a first digital-to-analog converter coupled between an output of the quantizer and an input of the first first-stage integrator; and
a second digital-to-analog converter coupled between the output of the quantizer and an input of the second first-stage integrator; and
a digital circuit coupled to the output of the quantizer.
14. The system of claim 13 , wherein the micro electro-mechanical device comprises a microphone.
15. The system of claim 13 , wherein the digital circuit comprises a decimation filter and a high-pass filter.
16. The system of claim 13 , wherein each of the integrators comprises a fully differential topology.
17. The system of claim 13 , wherein the first and second digital-to-analog converter is a single-bit converter and the quantizer is a single-bit quantizer.
18. The system of claim 13 , wherein the first and second digital-to-analog converter is a multi-bit converter and the quantizer is a multi-bit quantizer.
19. The system of claim 13 , wherein one of the first-stage integrators is configured as a negative phase integrator.
20. The system of claim 13 , wherein each of the first-stage integrators is configured as a positive phase integrator.