Reconfigurable Passive Noise-Shaping SAR ADC Without Dynamic Amplifiers
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Solution Overview
Problem
Existing passive noise shaping successive approximation register (SAR) analog-to-digital converters (ADCs) face challenges with high implementation complexity, poor stability, and high power consumption due to the need for dynamic amplifiers and multi-input comparators, while simpler configurations offer limited noise shaping capacity and accuracy.
Innovation Solution
A reconfigurable passive integral network within the noise shaping circuit, composed of sub-passive integrators, eliminates the need for operational amplifiers and multi-input comparators, allowing for simple circuit structure, low power consumption, and strong noise shaping capacity by reconfiguring the network in different phases to achieve any desired gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dynamic amplifiers and multi-input comparators are used in the noise shaping circuit, then the gain and noise shaping capacity are improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent combines multiple passive integrators into a single integrated noise shaping circuit that performs both integration and gain functions. The passive integrators are merged with the comparator input stage, eliminating the need for separate dynamic amplifiers and multi-input comparators. This integration maintains the required noise shaping capacity while significantly reducing device complexity.
Solution Approach 2:
The patent replaces active electronic components (dynamic amplifiers and multi-input comparators) with passive RC integrator circuits. By substituting active amplification mechanisms with passive integration followed by single-input comparator operations, the system achieves comparable noise shaping performance without the complexity of active gain stages.
2Power
If dynamic amplifiers are used to amplify integral signals, then the signal gain is improved, but the stability deteriorates
Solution Approach 1:
The patent replaces dynamic amplifiers with passive RC integrator circuits that inherently provide signal accumulation without active amplification. The passive nature of RC circuits ensures stability while the integration process provides the necessary signal gain through temporal accumulation rather than instantaneous amplification, eliminating stability issues associated with dynamic amplifiers.
3Measurement precision
If multi-input comparators are used to add signals, then the noise shaping capacity is improved, but the power consumption increases
Solution Approach 1:
The patent merges the signal addition function into the passive integration process itself. Instead of using multi-input comparators to sum signals after integration, the design combines multiple input signals through the passive RC integrators before comparison. This approach maintains noise shaping capacity while using only single-input comparators, significantly reducing power consumption.
Solution Approach 2:
The patent replaces active signal addition operations (performed by multi-input comparators) with passive RC integration that naturally sums input signals through current integration. This substitution eliminates the need for power-hungry multi-input comparator operations while preserving the noise shaping functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a SAR ADC with a simple circuit structure, low power consumption, and enhanced noise shaping capability, effectively utilizing hardware resources without additional hardware overhead, achieving stable and efficient signal amplification and noise reduction.
Implementation Method 1
the passive integrators acquire conversion residues on switch capacitor arrays and integrate and store the conversion residues
Implementation Method 2
the passive integrators adopt a principle of free charge exchange between capacitors to realize integration
Data Source
AI summary
The present application discloses a successive approximation register analog-to-digital converter with passive noise shaping, which comprises: switch capacitor arrays for acquiring analog input signals; a noise shaping circuit which is a passive integral network, the network has input ends connected respectively with output ends of the two switch capacitor arrays and for acquiring output signals of the two switch capacitor arrays, is composed of a plurality of sub passive integrators, and reconfigures the plurality of sub passive integrators to different circuit forms; a comparator which has two input ends connected respectively with output ends of the passive integral network and an output end connected with an input end of a logic circuit, and is configured to compare magnitudes of the output signals of the noise shaping circuit.