DAC Output Calibration Without Isolation Switches
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Solution Overview
Problem
Existing digital-to-analog converters (DACs) face calibration challenges due to interfering signals from other electrical components, particularly return loss from board blocks, which disrupt accurate measurement and calibration of the DAC output.
Innovation Solution
A method for DAC calibration that adjusts the clock signal to synchronize DAC output timing with return loss patterns, allowing calibration without isolating the DAC from other components, thereby mitigating interference and ensuring accurate calibration in situ.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional DAC calibration methods are used, then calibration can be performed, but interfering signals from board blocks and return loss disrupt accurate measurement and calibration
Solution Approach 1:
The patent applies preliminary action by measuring the return loss characteristics before performing DAC calibration. The system characterizes the interfering signals from board blocks in advance, stores these measurements, and then uses this pre-acquired information to compensate for interference during calibration, thereby improving measurement accuracy without requiring isolation switches.
Solution Approach 2:
The patent converts the harmful return loss interference into a beneficial measurement parameter. By measuring and characterizing the return loss signals, the system transforms these interfering signals into useful information that can be used to compensate for their effects during calibration, effectively turning the harmful interference into a tool for improving calibration accuracy.
2Measurement precision
If isolation switches are used to block interfering signals, then calibration accuracy improves, but circuit complexity increases
Solution Approach 1:
The patent extracts the interfering signal characteristics from the overall system and handles them separately through software-based compensation. Instead of physically isolating the DAC with switches, the system extracts return loss measurements, processes them independently, and applies compensation algorithms, thereby achieving accurate calibration without adding complex isolation circuitry.
Solution Approach 2:
The patent replaces the mechanical/electrical isolation switch system with a software-based signal processing system. Instead of using physical switches to block interfering signals, the system uses digital signal processing techniques to measure, characterize, and compensate for return loss effects, thereby reducing circuit complexity while maintaining calibration accuracy.
3Object-affected harmful factors
If DAC is isolated from other components during calibration, then interference is reduced, but calibration cannot be performed in situ
Solution Approach 1:
The patent implements feedback by continuously measuring the actual output signal during calibration, comparing it with the expected signal, and using the difference (including return loss effects) to adjust and compensate for interference. This feedback mechanism allows the system to perform accurate in situ calibration while the DAC remains connected to all other components, maintaining both interference reduction and adaptability.
Solution Approach 2:
The patent enables the DAC calibration system to serve itself by performing calibration in the actual operating environment without requiring external isolation or special test equipment. The system uses its own output signal, measures return loss effects, and compensates for them autonomously, allowing in situ calibration that adapts to the specific installation conditions.
Data Source
AI summary
Novel solutions for calibration of a digital-to-analog converter (DAC). Some solutions allow for the calibration of a DAC without an isolation switch and/or calibration based on signal measurements taken at the output stage of a device comprising the DAC.