Interpolative DAC Circuit With Fewer Switches and Simpler Routing
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Solution Overview
Problem
Conventional digital-to-analog converters require a large number of switches, leading to complex routing and a large layout area, which complicates the conversion process.
Innovation Solution
An interpolative digital-to-analog converter is designed with a router unit that receives and outputs specific bits of a digital signal to generate an analog signal through an interpolation unit, reducing the number of switches needed by using a multiplexer unit and interpolation unit to produce the desired analog voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional binary-tree decoding with multiple switches is used, then digital-to-analog conversion can be achieved, but the number of switches increases and routing becomes complicated
Solution Approach 1:
The digital signal bits are segmented into two groups: first and second bits control the router unit to select between first and second voltages, while the first bit controls the interpolation unit to perform weighted combination. This segmentation reduces the need for multiple switches by dividing the conversion function into distinct stages.
Solution Approach 2:
The router unit acts as an intermediary that selects two reference voltages based on the first and second bits, providing them as inputs to the interpolation unit. This intermediary structure simplifies the overall system by separating voltage selection from voltage combination functions.
2Measurement precision
If more switches are used for precise conversion, then conversion accuracy is improved, but layout area increases
Solution Approach 1:
The system changes the operational parameters by using an interpolation mechanism where the interpolation unit performs weighted combination of voltages based on the first bit. This parameter-based approach (using weight coefficients) achieves precise analog output without requiring a proportional increase in switch count and layout area.
Data Source
AI summary
An interpolative digital-to-analog (D/A) converter is adapted to convert a N-bit digital signal into an analog signal, where N is a positive integer greater than 1. The interpolative D/A converter includes a router unit that outputs first and second router voltages based on the first and second bits of the digital signal, and an interpolation unit that receives the first and second router voltages from the router unit, and that performs interpolation operation on the first and second router voltages according to the first bit of the digital signal, so as to generate the analog signal having a voltage magnitude ranging from the first router voltage to the second router voltage.