Converter IC Gain Control with Latency-Aligned Masking
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Solution Overview
Problem
Existing gain control systems face challenges in synchronizing updates between analog and digital gain stages, leading to signal transients and audible artefacts due to misaligned gain transitions.
Innovation Solution
A converter integrated circuit (IC) with integrated gain control circuitry synchronizes gain updates across multiple stages using a single circuit, compensating for signal path latency and employing zero-cross detection to align transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If discrete resistors and switches are used for digital gain control, then gain adjustment capability is improved, but synchronization between low-resolution and high-resolution gain stages deteriorates
Solution Approach 1:
The patent combines discrete resistor-based gain switching with digital potentiometer control into a unified gain control system. The low-resolution gain stages (first and second gain stages) using discrete resistors are merged with the high-resolution digital potentiometer stage, all under coordination by control circuitry that applies latency compensation to synchronize transitions across all stages simultaneously.
Solution Approach 2:
The control circuitry acts as an intermediary that receives a single gain control value and distributes it to multiple gain stages with different resolutions. It implements latency compensation by calculating and applying different delay values to different gain stages, ensuring they all transition at the correct time despite their different characteristics and positions in the signal path.
2Ease of operation
If analog potentiometer is used for continuous gain control, then gain control smoothness is improved, but digital controllability deteriorates
Solution Approach 1:
The patent replaces the traditional mechanical analog potentiometer with a digital potentiometer that can be controlled by digital signals. This substitution maintains the continuous gain adjustment capability of analog potentiometers while enabling full digital controllability through digital interfaces, allowing the gain control to be integrated into digital audio processing systems.
3Measurement precision
If multiple gain stages are used for high-resolution gain control, then gain precision is improved, but signal transition artifacts worsen
Solution Approach 1:
The control circuitry performs preliminary calculations to determine the appropriate latency compensation values for each gain stage before transitions occur. By pre-calculating and applying the correct delay values to each stage based on their individual characteristics and positions in the signal path, the system ensures that all stages transition simultaneously, preventing the generation of signal artifacts such as clicks or pops.
Data Source
AI summary
An integrated circuit (IC), comprising: a first converter configured to convert a first signal to a first output signal; an internal gain stage configured to apply a first gain to the first signal or the first output signal; a first output pin for outputting a signal derived from the first output signal; control circuitry configured to: output a first internal gain control signal to the internal gain stage to update the first gain of the internal gain stage; and output a mask control signal to a mask output pin of the IC, wherein output of the mask control signal is delayed relative to output of the first internal gain control signal by a predetermined mask delay, the predetermined mask delay to compensate for signal chain delay between the first gain stage and the masking circuitry.