Receiving Circuit Gain Control for Noise Filtering Without Bandpass Filters
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Solution Overview
Problem
The existing semiconductor devices with receiving circuits face challenges in reducing noise interference and circuit area, particularly when detecting electronic pen coordinates using electromagnetic induction methods, as noise mixes with the signal and requires large bandpass filters.
Innovation Solution
Incorporating a gain control circuit that samples and adjusts the gain of the receiving circuit during transmission periods, allowing for noise reduction without the need for a bandpass filter, thereby reducing the circuit area and improving signal detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a bandpass filter is used to remove noise from the received signal, then noise immunity is improved, but the circuit area increases
Solution Approach 1:
The patent extracts and removes the bandpass filter component from the receiving circuit. Instead of using a bandpass filter to remove noise, the invention samples the received signal during the transmission period and uses the sampling results to control the gain during the reception period, thereby eliminating the need for a bandpass filter and reducing circuit area while maintaining noise immunity
Solution Approach 2:
The patent replaces the traditional analog bandpass filter mechanism with a digital signal processing approach. By sampling the signal during the transmission period and using these samples to control gain during reception, the invention substitutes the mechanical/analog filtering system with a timing-based digital control system, achieving noise removal without the physical filter hardware
2Measurement precision
If the gain of the receiving circuit is increased to improve signal detection, then signal detection precision is improved, but noise interference increases
Solution Approach 1:
The patent performs preliminary sampling of the received signal during the transmission period before the actual reception period begins. These preliminary samples are used to determine the appropriate gain level, allowing the system to prepare the optimal gain setting in advance based on actual signal conditions, thereby improving detection precision while avoiding excessive noise amplification
Solution Approach 2:
The patent implements a feedback mechanism where the sampling results obtained during the transmission period are fed back to control the gain setting during the reception period. This feedback loop allows the system to automatically adjust the gain based on actual signal characteristics, achieving optimal signal detection precision while minimizing noise interference through adaptive control
3Object-affected harmful factors
If a bandpass filter is added to the receiving circuit to filter noise, then noise removal is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the bandpass filter from the circuit architecture. By using the transmission period to sample the signal and controlling gain during reception based on these samples, the invention removes the need for complex filtering circuitry, thereby reducing device complexity while maintaining effective noise removal capabilities
Solution Approach 2:
The patent changes the operational parameters of the receiving circuit by utilizing the transmission period for sampling and adjusting gain dynamically based on sampling results. This parameter-based control approach replaces the need for complex frequency-selective filtering, achieving noise removal through temporal parameter management rather than frequency domain filtering, thus reducing circuit complexity
Data Source
AI summary
The circuit area of the semiconductor device in which the transmission period and the reception period are alternately repeated is reduced. The semiconductor device includes a transmission circuit and a receiving circuit. The receiving circuit includes a gain control circuit that samples the input signal to adjust the gain of the receiving circuit during the reception period and adjusts the gain based on the sampling result during the transmission period.