ADC Dynamic DAC Gain Control for Low-Noise Recording
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Solution Overview
Problem
Current recording devices face challenges with noise from programmable gain amplifiers (PGA) and analog-to-digital converters (ADC) affecting recording performance, leading to increased power consumption and size, while gain adjustments within ADCs introduce operational amplifiers (OPA) that further increase power consumption.
Innovation Solution
An analog-to-digital conversion circuit with a dynamic range enhancement module and a digital-to-analog conversion module that dynamically controls DAC elements to adjust gain, eliminating the need for an OPA and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low-noise PGA is used to improve recording performance, then noise performance is improved, but power consumption and device size increase
Solution Approach 1:
The patent extracts the gain adjustment function from the traditional PGA component and relocates it to the digital domain within the ADC. By removing the PGA and implementing gain control through digital signal processing and dynamic element matching of DAC elements, the solution eliminates the need for a separate low-noise PGA component, thereby reducing power consumption and device size while maintaining noise performance
Solution Approach 2:
The patent replaces the analog mechanical/electrical gain adjustment mechanism (PGA) with a digital control mechanism. The gain is adjusted by dynamically controlling the number of DAC elements connected to the summing node, which is controlled by digital logic circuits. This substitution of analog gain control with digital control eliminates the need for high-performance analog components and reduces overall power consumption
2Adaptability or versatility
If an OPA is introduced to adjust gain inside the ADC, then gain adjustment capability is improved, but power consumption increases
Solution Approach 1:
The patent removes the OPA from the signal path by implementing gain adjustment entirely through digital means. The gain control is achieved by dynamically selecting the number of DAC elements (resistors) connected to the summing node, which is controlled by digital switch elements. This extraction of the OPA eliminates its power consumption while preserving the gain adjustment capability through digital element matching
Solution Approach 2:
The patent introduces digital switch elements as intermediaries between the DAC elements and the summing node. These switch elements, controlled by digital logic, dynamically connect or disconnect DAC elements based on the desired gain setting. This digital intermediary replaces the analog OPA, providing gain adjustment capability without the power consumption penalty of an operational amplifier
Data Source
AI summary
An analog-to-digital conversion circuit, a chip, and a recording device are provided. The analog-to-digital conversion circuit includes a main path module, a dynamic range enhancement module, and a dynamic digital-to-analog conversion module. The main path module converts an analog signal and an analog feedback signal into a digital signal to be processed, outputs the digital signal to be processed to the dynamic range enhancement module, and obtains a digital signal output according to the digital signal to be processed and the digital gain signal. The dynamic range enhancement module performs dynamic quantization processing on the digital signal to be processed to obtain at least one control signal and generate the digital gain signal. The dynamic digital-to-analog conversion module dynamically controls on and off of each of DAC elements in a digital-to-analog conversion array according to the at least one control signal and generates the analog feedback signal.