Multi-Dimensional DAC Current Mirroring for Low-Noise Output
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Solution Overview
Problem
Multi-dimensional DACs are susceptible to power supply noise and require additional area and power consumption due to the use of successive current mirrors.
Innovation Solution
Implement a current source mirroring technique using a current source coupled to a reference transistor, with multiple output paths and cells, each controlled by digital signals to output a mirrored current, reducing noise and area requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If successive current mirrors are used to achieve multi-dimensional DAC, then the output current can be generated, but the device is susceptible to power supply noise and requires additional area and power consumption
Solution Approach 1:
The patent segments the multi-dimensional DAC into multiple independent one-dimensional DACs, each handling a single dimension. This segmentation eliminates the need for successive current mirrors that chain multiple dimensions together, thereby reducing susceptibility to power supply noise while maintaining the multi-dimensional output capability through parallel operation of independent DAC units.
Solution Approach 2:
The patent introduces a summation circuit as an intermediary that combines the output currents from multiple independent one-dimensional DACs. This intermediary approach replaces the direct successive current mirror chaining, allowing each DAC to operate independently with its own current source, thus isolating them from power supply noise affecting other dimensions while still achieving the multiplicative multi-dimensional output.
2Adaptability or versatility
If successive current mirrors are used to achieve multi-dimensional DAC, then the output current can be generated, but additional area is required
Solution Approach 1:
By dividing the multi-dimensional DAC into separate one-dimensional DACs that operate in parallel, each DAC can use compact current source implementations without requiring the expansive successive current mirror structure. The segmentation allows independent optimization of each dimension's area while achieving the overall multi-dimensional functionality through their combined output.
Solution Approach 2:
The patent merges the output currents from multiple independent one-dimensional DACs using a summation circuit to achieve the multi-dimensional output effect. This merging approach consolidates the area requirements into parallel independent units rather than requiring the hierarchical expansion of successive current mirrors, thereby reducing total device area while maintaining adaptability.
3Adaptability or versatility
If successive current mirrors are used to achieve multi-dimensional DAC, then the output current can be generated, but power consumption increases
Solution Approach 1:
Segmenting the multi-dimensional DAC into independent one-dimensional units allows each segment to use its own efficient current source without the cumulative power overhead of successive current mirrors. Each segmented DAC can be optimized for minimal power consumption in its specific dimension, and the total power consumption is the sum of independent efficient units rather than the multiplicative overhead of chained mirrors.
Solution Approach 2:
The summation circuit acts as an intermediary that combines outputs from low-power independent DACs, avoiding the high power consumption inherent in successive current mirrors. This intermediary approach allows each DAC to operate at minimal power while still achieving the multi-dimensional output through efficient current summation rather than power-intensive mirroring.
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
The solution provides a reliable and efficient output current by minimizing noise, reducing device area, and improving settling time and switching performance.
Implementation Method 1
a current source, circuitry to mirror the current source (e.g., a current generated by the current source)
Data Source
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.