Current-Steering DAC Layout for Low Quiescent Current Noise
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Solution Overview
Problem
Current digital-to-analog converters, particularly those using current steering structures, face challenges in reducing noise generated by quiescent current while maintaining output signal amplitude and minimizing power consumption.
Innovation Solution
The proposed digital-to-analog converter design eliminates or reduces the second current source module, allowing the quiescent current to fully flow through the trans-impedance amplifier, thereby reducing noise and power consumption without increasing circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a single-side switch type current steering structure is used, then power consumption is reduced and switch delay problem is avoided, but double quiescent current overheads are needed and noise exponentially increases
Solution Approach 1:
The patent extracts and removes the second current source module from the conventional single-side switch type structure. By eliminating this module, the quiescent current that would have been consumed by it is completely eliminated, thereby reducing both power consumption and the noise generated by quiescent current while maintaining the output signal amplitude
Solution Approach 2:
The patent changes the operational parameters of the trans-impedance amplifier by allowing the quiescent current to fully flow through it without being divided or consumed by a second current source module. This parameter change optimizes the current utilization, reducing noise while maintaining the required output signal level
2Manufacturing precision
If a double-side switch type current steering structure is used, then output signal amplitude is achieved, but switch delay mismatch occurs and power consumption increases
Solution Approach 1:
The patent removes the second current source module and associated components from the double-side switch type structure, simplifying the circuit while maintaining output signal amplitude. This extraction eliminates the power consumption associated with the removed components without compromising the primary function
Solution Approach 2:
The patent adopts an asymmetric structure by using only one current source module instead of the symmetric double-side structure. This asymmetric design reduces power consumption and eliminates switch delay mismatch issues while still achieving the required output signal amplitude through optimized current steering
3Device complexity
If a single-side switch type current steering structure is used, then circuit complexity is reduced, but quiescent current overhead doubles and noise increases
Solution Approach 1:
The patent extracts and removes the second current source module from the single-side switch type structure. This extraction maintains the low circuit complexity advantage while eliminating the source of doubled quiescent current overhead and associated noise, achieving both simplicity and low noise performance
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
This approach significantly reduces noise and power consumption associated with quiescent current, maintaining the same output signal amplitude as existing single-side switch type structures while outperforming double-side switch types in power efficiency.
Implementation Method 1
the trans-impedance amplifier configured to: convert the current I1 supplied by the first current source module into an analog voltage, and output the analog voltage
Data Source
AI summary
A digital-to-analog converter includes a first current source module configured to supply a current I1 to the digital-to-analog converter, a first switch control module configured to control connection or disconnection between each branch and a trans-impedance amplifier in the digital-to-analog converter based on a to-be-converted digital signal, where the current I1 supplied by the first current source module flows to the trans-impedance amplifier through a connected branch, and the trans-impedance amplifier is configured to convert the current I1 supplied by the first current source module into an analog voltage and output the analog voltage.