Trans-impedance amplifier, chip, and communications device
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Solution Overview
Problem
Current trans-impedance amplifiers (TIAs) face a trade-off between power consumption and filtering performance, where reducing power consumption compromises filtering capability and out-of-band interference suppression.
Innovation Solution
A TIA design incorporating a single operational amplifier, three circuits with passive components, and a third circuit that cooperates with the first and second circuits to perform shaping filtering, enhancing filtering performance and out-of-band interference suppression while minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a first-order active structure TIA is used, then power consumption is reduced, but filtering capability deteriorates
Solution Approach 1:
The TIA is segmented into three distinct circuits: a first circuit for receiving and initial processing the current signal, a second circuit for differential signal processing, and a third circuit specifically dedicated to shaping filtering. This segmentation allows the filtering function to be isolated and optimized in the third circuit while the first-order active structure maintains low power consumption, thus resolving the contradiction between reduced power consumption and adequate filtering capability.
2Reliability
If a second-order active structure TIA is used, then filtering capability is improved, but power consumption increases
Solution Approach 1:
The filtering function is extracted from the main amplification path and implemented as a separate third circuit with passive components. This extraction allows the core amplification to be performed by a simple first-order active structure with low power consumption, while the filtering capability is provided by the dedicated third circuit, thus achieving second-order filtering performance without the power penalty of a conventional second-order active structure.
3Device complexity
If a first-order active structure TIA is used, then device complexity is reduced, but out-of-band interference suppression deteriorates
Solution Approach 1:
The third circuit acts as an intermediary between the differential amplification stage and the output, specifically designed to perform shaping filtering that suppresses out-of-band interference. This intermediary circuit with passive components adds minimal complexity while effectively addressing the harmful out-of-band interference, thus resolving the contradiction between simple device structure and interference suppression capability.
Data Source
AI summary
A trans-impedance amplifier (TIA) includes a first circuit, a second circuit, and a third circuit. Both the first circuit and the second circuit are coupled to a current source, an operational amplifier, and the third circuit. The first circuit is configured to receive a first current, provide a third voltage to the third circuit, perform shape filtering on the first current, and convert the shape filtered first current to a first voltage for output. The second circuit is configured to receive a second current, provide a fourth voltage to the third circuit, perform shape filtering on the second current, and convert the shape filtered second current to a second voltage for output. The third circuit is configured to cooperate with the first circuit and the second circuit in performing shape filtering. The operational amplifier is configured to provide a small-signal virtual ground point to the first circuit.