Dynamic Common-Mode Control for Low-Level Differential Signals
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Solution Overview
Problem
Conventional digital-to-analog converters have a fixed common-mode DC voltage setting, which does not provide peak performance for low-level signals, leading to suboptimal performance in terms of noise, distortion, and power consumption.
Innovation Solution
Implementing a dynamic common-mode adjustor that varies the common-mode setting of a differential signal based on the magnitude of the input signal, using techniques such as mapping information or piece-wise linear functions to derive an offset and adjust the common-mode setting, thereby improving system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a fixed common-mode DC voltage setting is used in a conventional digital-to-analog converter, then the full-scale output signal swing is optimized, but the performance for low-level signals deteriorates
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed common-mode voltage setting to a dynamic common-mode voltage setting that adapts based on the input signal magnitude. The common-mode voltage is adjusted dynamically according to the absolute value of the input signal, allowing the system to optimize performance for both full-scale and low-level signals. This is implemented through circuitry that modifies the common-mode voltage in response to the input signal level, resolving the contradiction between power consumption optimization and signal conversion accuracy.
2Device complexity
If a fixed common-mode DC voltage setting is used, then the circuit design is simple, but the noise and distortion performance for low-level signals deteriorates
Solution Approach 1:
The patent implements dynamics by making the common-mode voltage setting dynamic rather than fixed. The common-mode voltage adjusts automatically based on the input signal magnitude, which reduces noise and distortion for low-level signals while maintaining full-scale signal performance. This dynamic adjustment resolves the contradiction between circuit simplicity and harmful factors by introducing adaptive control that targets specific signal conditions.
3Ease of operation
If a fixed common-mode setting is used to optimize full-scale output, then the system is easy to operate, but it does not provide peak performance at low level signals
Solution Approach 1:
The patent applies self-service by enabling the common-mode voltage setting to automatically adjust based on the input signal magnitude without requiring external control or configuration. The system monitors its own input signal level and autonomously modifies the common-mode voltage to optimize performance, thereby maintaining ease of operation while improving signal conversion reliability across different signal levels.
Data Source
AI summary
An apparatus such as an electronic circuit includes an input operable to receive an input signal; a dynamic common mode adjustor operable to: i) derive a differential signal from the received input signal, and ii) control an offset of the differential signal as a function of the received input signal to produce an offset differential signal; and an output operable to output the offset differential signal. In one arrangement, the offset differential signal outputted from the output includes a first signal and a second signal; a difference between the second signal and the first signal proportionally varies with respect to the received input signal.