Resistive DAC Force-Sense Routing for Low Distortion Output
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Solution Overview
Problem
Digital-to-analog converters (DACs) face challenges in achieving high dynamic range and reducing distortion due to parasitic impedances in combined force and sense paths, which can impact the integrity of analog signals, especially in high dynamic range applications.
Innovation Solution
The implementation of separate force and sense paths in DACs, along with a voltage reference generator that compensates for impedance variations, minimizes the impact of parasitic impedances and ensures low distortion by synchronizing on-chip and off-chip impedances, thereby reducing errors in output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If combined force and sense paths are used in DAC, then device complexity is reduced, but parasitic impedances cause signal distortion and degrade analog signal integrity
Solution Approach 1:
The patent divides the combined force and sense path into separate independent paths. The force path carries the output current from the DAC to the amplifier, while the sense path carries the sense voltage from the amplifier back to the DAC. This segmentation eliminates the interaction between force and sense currents, removing parasitic impedance distortion while maintaining manageable device complexity through modular path design.
2Object-affected harmful factors
If separate force and sense paths are implemented, then parasitic impedance impact is minimized, but device complexity increases
Solution Approach 1:
The patent merges the separate force and sense paths at the amplifier stage, where the sense voltage is taken from the amplifier output and fed back to the DAC. This merging approach allows the paths to be physically separate during critical signal transmission (reducing distortion) while being integrated at the processing stage (managing complexity). The amplifier acts as a convergence point that simplifies the overall system architecture.
3Measurement precision
If impedance compensation is implemented, then output voltage accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback through the sense path, where the sense voltage from the amplifier output is fed back to the DAC. This feedback mechanism allows the system to automatically compensate for impedance variations by adjusting the reference voltage based on actual output conditions. The feedback loop provides real-time correction, improving output voltage accuracy while using the existing sense path infrastructure to minimize additional complexity.
Data Source
AI summary
Described herein are DACs with low distortion for high dynamic range (HDR), extremely high dynamic range (EHDR), and other suitable applications. Some embodiments relate to a device including a DAC configured for coupling to an amplifier via a force path and a sense path. For example, the DAC may provide output current to the amplifier via the force path, and the DAC may sense the input voltage of the amplifier via the sense path. Accordingly, distortion such as harmonic distortion and/or gain offset from parasitic impedances in the force and/or sense paths may be reduced or eliminated. Some embodiments relate to a DAC including a voltage reference generator configured to compensate for variations in impedances of the DAC, such as due to semiconductor process variation. Accordingly, distortion in the DAC output due to variations in the DAC impedances may be reduced or eliminated.