Amplifier Offset Calibration Using Edge Timing Polarity Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Analog amplifiers, including switching amplifiers, often suffer from DC voltage offset, which can cause undesirable click/pop noises and degrade sound quality during operational state changes, such as muting, due to non-zero DC voltage at the output terminal when zero DC voltage is provided at the input.
Innovation Solution
An amplifying circuit comprising a signal processor, edge detector, and calibration controller that transforms amplitude information of input signals into the time domain, detects voltage offset polarity from the timing relationship of output signals, and compensates the offset through a calibration process, adjusting input signals to minimize or eliminate the offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an amplifier operates in switching mode to improve efficiency, then power consumption is reduced, but DC voltage offset occurs causing click/pop noises
Solution Approach 1:
The patent applies preliminary action by performing offset calibration before normal amplifier operation. The calibration phase pre-adjusts the offset compensation parameters using test signals, so that when the amplifier enters mute or standby states, the pre-calibrated parameters prevent DC voltage offset and associated click/pop noises without requiring continuous calibration.
2Measurement precision
If calibration operations are performed continuously to reduce DC voltage offset, then offset accuracy is improved, but system complexity and processing time increase
Solution Approach 1:
The patent implements periodic action by performing calibration operations at specific intervals and states rather than continuously. Calibration is executed during designated calibration phases when test signals are applied, and the results are stored for use during normal operation. This periodic approach maintains offset accuracy while reducing computational burden and system complexity compared to continuous calibration.
Data Source
AI summary
An amplifying circuit is provided and includes a signal processor, an edge detector, and a calibration controller. The signal processor transforms amplitude information of a first and second input signals into time domain to provide first and second output signals respectively. The edge detector detects a polarity of a voltage offset from a timing relationship of the first and second output signals. The calibration controller compensates the voltage offset according to a change of the detected polarity.