Dynamic Common-Mode Control for Low-Level Differential DAC Signals
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Solution Overview
Problem
Conventional differential digital-to-analog converters have a fixed common-mode DC voltage setting, which limits their performance at low signal levels and does not optimize noise, distortion, and power consumption.
Innovation Solution
A dynamic common-mode adjustor is introduced to vary the offset of the differential signal based on the magnitude of the input signal, allowing for signal-dependent common-mode control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fixed common-mode DC voltage setting is used in a conventional differential digital-to-analog converter, then the full-scale output signal swing is optimized, but the performance at low signal levels 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 varies with the input signal magnitude. The common-mode voltage is adjusted based on the absolute value of the input signal, allowing the system to adapt to different signal levels and optimize performance across the full operating range, particularly improving low signal level performance while maintaining full-scale output swing.
2Device complexity
If a fixed common-mode setting is used, then the circuit structure remains simple, but noise, distortion, and power consumption performance deteriorates
Solution Approach 1:
The patent applies the parameter changes principle by dynamically adjusting the common-mode voltage parameter based on the input signal magnitude. Instead of keeping the common-mode voltage fixed, the system varies this parameter according to the absolute value of the input signal, thereby optimizing noise, distortion, and power consumption performance without requiring a fundamentally complex circuit architecture.
3Object-affected harmful factors
If a dynamic common-mode adjustor is introduced to vary the offset based on input signal magnitude, then noise, distortion, and power consumption performance is improved, but the device complexity increases
Solution Approach 1:
The patent applies the intermediary principle by introducing a common-mode adjustor circuit that acts as a mediator between the input signal and the differential digital-to-analog converter. This adjustor dynamically modifies the common-mode voltage based on the input signal magnitude, thereby improving performance metrics while isolating the complexity to a dedicated control circuit rather than the entire system.
Data Source
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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.