RC-Coupled Multi-Stage Amplifier for DSDS Input Matching
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Solution Overview
Problem
In dual subscriber identity module (SIM) dual standby (DSDS) systems, the need to maintain the main amplifier on to preserve input matching while using an auxiliary high impedance amplifier for receiving paging signals leads to increased power consumption, even when there is no main receive signal, which reduces battery life.
Innovation Solution
The implementation of a resistive-capacitive (RC) network that selectively modifies the input impedance of the amplifier, allowing the auxiliary LNA to operate independently of the main LNA, enabling input impedance matching without activating the main LNA when not needed, using a split cascode architecture with separate cascode transistors for each carrier and an AC coupling capacitor to adjust impedance based on operational mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main amplifier is kept on to preserve input matching, then input impedance matching is maintained, but power consumption increases
Solution Approach 1:
The patent implements dynamic switching between different amplifier configurations based on operational mode. A control circuit selectively enables or disables the main amplifier and auxiliary amplifier depending on whether the system is in carrier aggregation mode or DSDS mode, allowing the input impedance matching network to adapt its configuration dynamically rather than maintaining a fixed state
Solution Approach 2:
The input impedance matching network is designed to serve multiple functions: it can operate with the main amplifier in carrier aggregation mode, switch to auxiliary amplifier-only operation in DSDS mode, and automatically adjust its impedance configuration based on the operational mode detected by the control circuit, eliminating the need for separate matching networks for different modes
2Use of energy by moving object
If the auxiliary LNA operates independently without the main LNA, then power consumption is reduced, but input impedance matching becomes difficult
Solution Approach 1:
The patent introduces an intermediate impedance transformation stage between the auxiliary amplifier and the input node. This intermediate network acts as a mediator that transforms the high output impedance of the auxiliary amplifier into a matched input impedance, enabling independent operation while maintaining proper impedance matching
Solution Approach 2:
The patent changes the impedance parameters of the matching network based on operational mode. When switching from carrier aggregation mode to DSDS mode, the control circuit reconfigures the impedance values of the matching network components to optimize performance for auxiliary amplifier-only operation, allowing the same hardware to achieve proper matching in both modes
Data Source
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AI summary
An apparatus includes a first amplifier stage configured to amplify a first carrier signal. The apparatus includes a second amplifier stage configured to amplify a second carrier signal. A resistive-capacitive (RC) network is coupled to the first amplifier stage and to the second amplifier stage. The RC network includes a resistive element coupled to a capacitive element.