Resistive Interpolation DAC for High Resolution in Less Area
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Solution Overview
Problem
Existing digital-to-analog converters (DACs) for IoT devices require a large number of resistors and switches to achieve high resolution, leading to increased circuit footprint and manufacturing costs.
Innovation Solution
A digital-to-analog converter that includes a decoding stage and an interpolation stage, where the decoding stage defines upper and lower bounds based on the most-significant portion of the digital value, and the interpolation stage outputs an interpolated value between these bounds based on the least-significant portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistor strings are used to achieve high resolution in DAC, then the resolution is improved, but the circuit footprint and manufacturing cost increase
Solution Approach 1:
The patent divides the digital input into two segments: most-significant bits (MSB) and least-significant bits (LSB). The MSB controls a coarse resistor string that defines upper and lower bounds, while the LSB controls a fine interpolation stage that selects values between these bounds. This segmentation allows high resolution to be achieved without requiring a single large resistor string, thereby reducing the circuit footprint while maintaining precision.
2Measurement precision
If more resistors and switches are used to increase DAC resolution, then the resolution is improved, but the manufacturing cost increases
Solution Approach 1:
By segmenting the resolution requirements into coarse (MSB) and fine (LSB) components, the patent reduces the total number of resistors and switches needed. The coarse stage uses fewer components to establish bounds, and the fine interpolation stage uses even fewer components to select between these bounds, thereby reducing manufacturing complexity and cost while achieving high overall resolution.
Solution Approach 2:
The patent transitions from a one-dimensional approach (single resistor string) to a two-dimensional approach (coarse bounds definition + fine interpolation). This dimensional change allows the system to achieve high resolution through combination of two lower-resolution stages rather than one high-resolution stage, reducing component count and manufacturing cost.
Data Source
AI summary
A digital-to-analog converter that outputs an analog value representing a digital value includes a decoding stage and an interpolation stage. The decoding stage defines upper and lower bounds and the interpolation stage outputs an interpolated value that is between the upper and lower bounds. The upper and lower bounds are based on a most-significant portion of the digital value. The interpolation stage selects the interpolated value based on the least-significant portion of the digital value.