High-Speed DAC Timing Alignment for Waveform Distortion
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Solution Overview
Problem
At ultra-high speed conversion rates, such as exceeding 100 GS/s, digital-to-analog converters face distortion issues due to differences in propagation delay within the circuit, causing misalignment of rising and falling edges in the analog signal waveform.
Innovation Solution
A digital-to-analog converter design incorporating multiple constant current sources, switch circuits, a load resistor, and timing adjustment circuits that align digital signal inputs to offset signal propagation delays, using clock signal timing adjustments and phase shifters to prevent waveform distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conversion speed is increased to exceed 100 GS/s, then the productivity of the digital-to-analog converter is improved, but the analog signal waveform becomes distorted due to propagation delay differences in each signal path
Solution Approach 1:
The patent applies preliminary action by introducing timing adjustment circuits that advance or delay the timing of digital signals before they reach the switch circuits. This preliminary timing adjustment compensates for the propagation delay differences that will occur in each signal path, ensuring that all signals arrive at the output simultaneously even at ultra-high conversion speeds exceeding 100 GS/s, thereby preventing waveform distortion
2Measurement precision
If timing alignment is performed using conventional methods at ultra-high speeds, then the timing of rising and falling edges is aligned at driving points, but propagation delay differences inside the core circuit still cause waveform distortion
Solution Approach 1:
The patent introduces timing adjustment circuits as intermediary elements between the digital signal input and the switch circuits. These intermediary circuits actively measure and compensate for propagation delay differences in each signal path, serving as mediators that ensure all signals arrive at the output simultaneously. This intermediary timing adjustment layer enables precise waveform accuracy even at ultra-high conversion speeds where conventional timing alignment methods fail
Data Source
AI summary
A digital-to-analog converter includes a core circuit including a plurality of input terminals for multi-bit digital signals, an output terminal for an analog signal, a plurality of constant current sources, a plurality of switch circuits connected in series to respective constant current sources of the plurality of constant current sources, and a load resistor connected to the output terminal. The core circuit being configured to select whether or not to allow a current to flow through each of the plurality of switch circuits based on the multi-bit digital signals and output a voltage generated by allowing the current flowing through each of the plurality of switch circuits to flow through the load resistor from the output terminal as an analog signal.