Feed-forward multi-bit quantization sigma-delta modulator

Abstract

The invention discloses a feed-forward multi-bit quantization sigma-delta modulator which comprises four stages of integrators and a multi-bit quantizer which are connected in sequence, and the output end of the multi-bit quantizer is fed back to the input end of the first-stage integrator through a DEM logic unit and a feedback DAC unit which are connected in series in sequence; and the last stage of integrator simultaneously completes summation and integral amplification of feedforward signals of other integrators. According to the feed-forward multi-bit quantization sigma-delta modulator provided by the invention, the last-stage integrator simultaneously completes signal integral amplification and feed-forward signal summation, an active adder is saved, the circuit design complexity is reduced, the power consumption is saved, and good performance can be achieved. The first-stage integrator circuit simultaneously adopts double sampling and chopping stabilization technologies, the chopping stabilization technology can effectively reduce low-frequency noise and compensate operational amplifier imbalance, the double sampling technology reduces the slew rate of an operational amplifier and the design requirement of unity gain bandwidth, and the area and power consumption of the circuit are optimized.

Description

technical field [0001] The invention relates to the field of signal processing, in particular to a feedforward multi-bit quantized Σ-Δ modulator. Background technique [0002] The sigma-delta ADC, an oversampling ADC that samples at a much higher frequency than the signal Nestle, has become a practical solution for high-precision ADC designs. It is widely used in electronic systems such as military, aerospace, audio, video, communication, radar, seismic exploration, medical treatment and testing. [0003] In the entire Σ-Δ ADC, the Σ-Δ analog modulator is the core of the entire ADC, and the performance of the modulator determines the accuracy and power consumption that the entire system can achieve. The traditional modulator structure is mainly divided into feedforward type and feedback type, in which the negative feedback of the feedforward structure makes the modulator input signal completely canceled at the input end of the loop filter, and the noise transfer function is...

AI Technical Summary

Problems solved by technology

[0006] figure 1 The output of each stage of the integrator needs to be connected to the feedforward adder and then input to the quantizer after being weighted and summed according to the feedforward coefficient, so an independent active adder is required, thus increasing the circuit area and power consumption

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