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US 7,352,311 B2Granted
Continuous time noise shaping analog-to-digital converter
AssigneeFreescale Semiconductor, Inc.
InventorsMatthew R. Miller, Pallab Midya, Poojan A. Wagh
Life of this patent
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Abstract
A system for a continuous time noise shaping analog-to-digital converter (“ADC”) with a suppressed carrier pulse width modulated (“PWM”) quantizer is disclosed. In particular, a suppressed carrier feedback signal may expand the dynamic range of a sigma delta modulated ADC and enhance the stability of the noise shaping loop.
Claims20
A system for performing analog-to-digital conversion (“ADC”) with a pulse width modulated (“PWM”) feedback signal comprising:
- a summer receiving an input signal, at least one feedback signal and generating an output error signal;
- a noise shaping filter coupled with the summer and configured to receive and filter the error signal;
- a first quantizer coupled with the noise shaping filter and configured to receive the filtered error signal and generate a first PWM signal;
- an inverter coupled with the noise shaping filter and configured to invert the filtered error signal;
- and
- a second quantizer coupled with the inverter and configured to receive the inverted filtered error signal and generate a second PWM signal;
- wherein the first PWM signal and the second PWM signal are fed back into the summer.
4 more elements
An analog-to-digital converter comprising:
- a summer configured to receive an input signal and at least one feedback signal and generate an error signal;
- a plurality of quantizers each configured to receive the error signal and generate a pulse width modulated (“PWM”) feedback signals based on the error signal, wherein the PWM feedback signals are fed back into the summer as the at least one feedback signal;
- and
- an inverter coupled with one of the plurality of quantizers and configured to invert the error signal inputted into that quantizer.
1 more element
A method for converting an analog input signal to a digital output signal comprising:
- receiving an input signal;
- summing the input signal with feedback signals to generate an error signal;
- generating the feedback signals based on the error signal with at least one quantizer;
- inverting one of the feedback signals;
- and
- combining the feedback signals including the inverted feedback signal with the input signal to adjust the error signal.
3 more elements
Dependencies are inferred from the claim text.