TDD Power Amplifier Current Monitoring with Frame-Synced Stabilization
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Solution Overview
Problem
Current TDD power amplifier systems face challenges in accurately measuring drain current due to slow data polling on non-time synchronized digital buses, which is inadequate for real-time operation in modern cellular communication systems like LTE and 5G NR.
Innovation Solution
A current monitoring circuit is introduced, comprising a voltage measurement circuit and a stabilizer circuit with a switch, resistors, and capacitors, which generates current equivalent voltage signals and stabilizes them during transmit frames, allowing for accurate current measurement even in non-time synchronized digital buses by disconnecting the stabilizer during receive frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If data polling is performed using a digital bus in TDD power amplifier systems, then current measurement functionality is achieved, but measurement speed is slow and cannot be synchronized with TDD switch points
Solution Approach 1:
The stabilizer circuit performs preliminary action by holding the voltage across the sense resistor constant during receive mode before the actual current measurement is needed. This pre-stabilization ensures that when transmit mode begins, the measurement can immediately capture accurate current data without waiting for slow digital bus polling to initialize.
Solution Approach 2:
The stabilizer circuit acts as an intermediary between the sense resistor and the digital bus polling system. It mediates the measurement process by maintaining a stable voltage reference that allows accurate current calculations even when the digital bus polling occurs at slower, non-synchronized intervals.
2Use of energy by moving object
If the power amplifier is switched off during receive mode to reduce power consumption, then energy efficiency is improved, but current measurement synchronization with TDD frame structure becomes difficult
Solution Approach 1:
The stabilizer circuit performs preliminary action by maintaining a held voltage state during receive mode that corresponds to the expected transmit mode current conditions. This pre-preparation ensures that when the power amplifier switches to transmit mode, the measurement system is already synchronized and ready to accurately capture current data at the correct TDD frame timing points.
Solution Approach 2:
The system uses feedback from the TDD frame structure to control the stabilizer circuit's switching. The stabilizer circuit receives feedback about when transmit and receive modes occur and adjusts its voltage holding behavior accordingly, ensuring measurements are always synchronized with the TDD frame structure regardless of the power amplifier's switched state during receive mode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise and synchronized current measurements in TDD power amplifiers, improving the accuracy and timing of current readings, thus supporting real-time operation in cellular communication systems.
Implementation Method 1
The capacitor coupled in series with the first resistor. The capacitor is further coupled to ground.
Data Source
AI summary
A current monitoring circuit for a TDD power amplifier in a communication system is provided. The current monitoring circuit includes a voltage measurement circuit and a stabilizer circuit. The voltage measurement circuit is configured to generate current equivalent voltage output signals associated with the TDD power amplifier. The stabilizer circuit has an output that is coupled to an analog-to-digital converter. The stabilizer circuit includes a switch, a first resistor, a capacitor and a first voltage supply. The switch includes a first post that is coupled to an output of the voltage measurement circuit. The first resistor has a first side coupled to a second post of the switch. The capacitor coupled in series with the first resistor. The capacitor is further coupled to ground. The first voltage supply is coupled to control the switch based on operations of a TDD power amplifier.