Parallel SA Flash ADC Circuit for High-Bit Conversion With Less Area
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Solution Overview
Problem
Conventional Flash ADC circuits face challenges in reducing chip area and power consumption as the number of bits in the digital output signal increases, leading to geometrically higher circuit elements and increased power usage.
Innovation Solution
The implementation of a multiple-bit parallel successive approximation (SA) Flash ADC circuit, which employs a multiple-output digital-to-analog converter (DAC) circuit and parallel comparator stages to generate digital output signals, reducing the number of circuit elements and maintaining similar conversion time to conventional Flash ADC circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Flash ADC circuits use more comparator circuits to generate digital output signals with a greater number of bits, then the number of bits in the digital output signal increases, but the chip area and power consumption increase geometrically
Solution Approach 1:
The ADC conversion process is segmented into multiple parallel comparator stages, where each stage handles a subset of the digital bits. Instead of using one large array of comparators, the circuit divides the comparison task across several stages, each with fewer comparators, thereby reducing the total chip area while maintaining high-resolution output.
Solution Approach 2:
The patent transitions from a single-dimensional array of comparators to a multi-dimensional hierarchical structure with parallel stages. This dimensional change allows the system to achieve the same bit resolution with a more compact arrangement, reducing the geometric growth of chip area.
2Measurement precision
If conventional Flash ADC circuits use more comparator circuits to generate digital output signals with a greater number of bits, then the number of bits in the digital output signal increases, but the power consumption increases geometrically
Solution Approach 1:
The power consumption is segmented across multiple parallel stages, where each stage consumes less power individually. By distributing the total comparison workload across stages rather than using a single large comparator array, the overall power consumption is reduced while achieving the same high-bit resolution output.
3Measurement precision
If conventional Flash ADC circuits are designed for higher bit resolution, then the number of bits increases, but the number of circuit elements increases geometrically
Solution Approach 1:
The circuit elements are segmented into multiple parallel comparator stages, each handling a portion of the bit resolution. This segmentation reduces the number of circuit elements required in each stage while maintaining the overall high-bit resolution capability through the combined output of all stages.
Solution Approach 2:
Each parallel comparator stage is designed with universal functionality to handle multiple bits of resolution. The stages can be replicated and combined, allowing the system to achieve higher bit resolution without proportionally increasing the complexity of individual circuit elements.
Data Source
AI summary
Multiple-bit parallel successive approximation (SA) Flash analog-to-digital converter (ADC) circuits are disclosed. In one aspect, a multiple-bit parallel SA Flash ADC circuit includes a digital-to-analog converter (DAC) circuit that receives reference voltage and trial bit codes, and generates DAC analog signals. The SA Flash ADC circuit includes parallel comparator stages, each including one or more comparator circuits equal to two (2) raised to a number of digital bits of the corresponding parallel comparator stage, quantity minus one (1). Each comparator circuit receives an analog input signal and corresponding DAC analog signal, and generates a digital signal. The digital signal of each comparator circuit is logic high if the analog input signal has a greater voltage than the corresponding DAC analog signal, and logic low if the analog input signal has a smaller voltage. The digital signals corresponding to each parallel comparator stage are used to generate a digital output signal.