Multi-Dimensional DAC Current Mirror Layout for Low-Noise Settling
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Solution Overview
Problem
Existing multi-dimensional digital-to-analog converters (DACs) using successive current mirrors are susceptible to power supply noise, require additional area and power consumption, and suffer from delayed settling time and inefficient device control.
Innovation Solution
The implementation of a multi-dimensional DAC that mirrors a current source using a reliable and efficient method, incorporating a current source, a transistor, and a plurality of cells with switches and transistors to output a current corresponding to the product of two digital signals, thereby reducing noise susceptibility and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If successive current mirrors are used to achieve multi-dimensional DAC, then the output current can be multiplicative in terms of input control words, but the system becomes susceptible to power supply noise
Solution Approach 1:
The patent divides the current mirror system into multiple independent parallel current mirrors, each handling a specific dimension of the multi-dimensional DAC. This segmentation isolates the power supply noise affecting each mirror, preventing noise propagation across the entire system while maintaining multi-dimensional output capability.
Solution Approach 2:
The patent introduces dummy transistors as intermediary elements that mirror the power supply noise characteristics. These dummy transistors are connected in a way that their noise contribution cancels out the noise from the actual current mirrors, effectively filtering power supply noise while preserving the multiplicative output function.
2Adaptability or versatility
If multiple input control signals and successive current mirrors are used, then multi-dimensional output is achieved, but device area and power consumption increase
Solution Approach 1:
The patent merges multiple current mirror functions into a unified parallel architecture where multiple current mirrors share common circuit elements and control signal pathways. This consolidation reduces the total device area required compared to successive current mirrors while maintaining the ability to produce multiplicative output currents from multiple input control words.
3Adaptability or versatility
If multiple input control signals and successive current mirrors are used, then multi-dimensional output is achieved, but power consumption increases
Solution Approach 1:
The patent combines multiple current mirror operations into a parallel structure that shares power supply connections and control signal distribution networks. This merging eliminates redundant power consumption associated with successive current mirrors while preserving the multi-dimensional output functionality through coordinated control of the parallel mirrors.
4Adaptability or versatility
If successive current mirrors are used, then multi-dimensional DAC function is achieved, but settling time is delayed
Solution Approach 1:
The patent segments the current mirror operation into parallel independent stages rather than successive sequential stages. Each parallel current mirror settles independently and simultaneously, eliminating the cumulative settling time delays inherent in successive current mirrors while maintaining the multi-dimensional output capability through coordinated control.
5Adaptability or versatility
If successive current mirrors are used, then multi-dimensional DAC function is achieved, but device control efficiency is reduced
Solution Approach 1:
The patent implements dynamic control of parallel current mirrors through independently controllable switches for each mirror. This dynamic architecture allows flexible and efficient control of the multi-dimensional output by selectively enabling or disabling specific current mirrors based on the input control words, improving device control efficiency compared to fixed successive current mirror configurations.
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 reduces noise susceptibility, minimizes device area and power consumption, and enhances settling time and switching performance by independently controlling the output current through the digital signals.
Implementation Method 1
a transistor coupled to the current source, wherein the transistor mirrors the current source
Data Source
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AI summary
A device may include a digital-to-analog converter, DAC, including a current source, circuitry to mirror the current source, the circuitry including a transistor coupled to the current source, and a plurality of output paths, each output path of the plurality of output paths including a first switch to selectively configure a first transistor to mirror the current source, wherein each output path corresponds to a value of a respective bit of a first digital signal, and a plurality of cells, each cell of the plurality of cells including a second switch to selectively couple a second transistor to a corresponding one of the plurality of output paths, wherein each of the plurality of cells corresponds to a value of a respective bit of a second digital signal.