Power Amplifier Current and Voltage Detection Correction
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Solution Overview
Problem
Varying Voltage Standing Wave Ratio (VSWR) due to environmental factors affects load impedance in mobile terminal power amplifiers, leading to excessive current drain and spectral noise, reducing battery life and distorting modulation patterns.
Innovation Solution
A system with over current and over voltage detection and correction circuitry that compares output current and voltage signals to maximum thresholds during ramp-up, reducing the power control signal to prevent excessive current and voltage, thereby maintaining target output power and reducing spectral noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the supply voltage is increased to provide target output power when load impedance is high, then the output power is maintained, but the battery voltage reaches maximum limit causing spectral noise and waveform distortion
Solution Approach 1:
The system performs preliminary detection of current and voltage during the ramp-up phase before full power is applied. By detecting whether current or voltage exceeds expected thresholds during ramp-up, the system can preemptively reduce the power control signal to prevent saturation and spectral noise, rather than reacting after the harmful effects occur.
Solution Approach 2:
The system continuously monitors output current and voltage during ramp-up and uses this feedback to adjust the power control signal. When current or voltage exceeds the maximum ramp thresholds, the feedback mechanism reduces the power control signal to keep the amplifier operating within safe limits, preventing waveform distortion and spectral noise.
2Power
If the supply voltage is increased to compensate for high load impedance, then the target output power is achieved, but excessive current drain occurs reducing battery life
Solution Approach 1:
The system performs preliminary detection of current during the ramp-up phase to identify conditions that would lead to excessive current drain. By detecting current thresholds before full power is applied, the system can preemptively reduce the power control signal to prevent excessive battery discharge, rather than allowing high current to drain the battery after the fact.
Solution Approach 2:
The system continuously monitors output current during ramp-up and uses feedback to adjust the power control signal. When current exceeds the maximum ramp threshold, the feedback mechanism reduces the power control signal to prevent excessive current drain on the battery, thereby extending battery life while maintaining acceptable output power.
3Object-generated harmful factors
If the power control signal is reduced to prevent saturation, then spectral noise and distortion are avoided, but the output power falls below target level
Solution Approach 1:
The system applies partial correction by reducing the power control signal only when and to the extent necessary to prevent saturation. During normal operation, the full power control signal is applied to achieve target output power. Only when current or voltage detection indicates approaching saturation limits does the system apply partial reduction to prevent harmful effects, rather than continuously reducing power.
Data Source
AI summary
A system and method for detecting and correcting excess current in a power amplifier in a transmit chain of a mobile terminal are provided. Over current detection and correction circuitry compares a current detection signal indicative of an output current of the power amplifier to a maximum current ramp during ramp-up for a transmit burst. If the current detection signal exceeds the maximum current ramp, then a power control signal controlling a supply voltage provided to the power amplifier circuitry is reduced, thereby reducing the output power and output current. Over voltage detection and correction circuitry compares a voltage detection signal indicative of an output voltage of the power amplifier to a maximum voltage ramp during ramp-up for the transmit burst. If the voltage detection signal exceeds the maximum voltage ramp, then the power control signal is reduced.