RF Power Amplifier Bias Switching for Data-Rate Power Saving
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Solution Overview
Problem
Portable electronic devices with small batteries face challenges in maintaining battery life due to high power consumption, especially in wireless communications devices that require efficient power management to support varying data rates and transmission modes.
Innovation Solution
The implementation of adjustable power supply voltage circuitry that dynamically adjusts the bias voltage for power amplifier circuitry based on data transmission rates, output powers, and operating modes, using a look-up table to optimize power consumption while ensuring linear signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high bias voltage is supplied to power amplifier circuitry to ensure sufficient headroom for high-data-rate signals, then transmission performance is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic bias voltage adjustment by monitoring data rate parameters and automatically adjusting the bias voltage supplied to the power amplifier circuitry. The system transitions from static to dynamic operation, adapting the bias voltage in real-time based on actual transmission requirements. This resolves the contradiction by ensuring high performance only when high data rates are actually being transmitted, rather than maintaining high bias voltage continuously.
Solution Approach 2:
The system changes the operating parameter (bias voltage) based on the data rate being transmitted. When high data rates are detected, the bias voltage is increased to provide sufficient headroom and prevent nonlinearities. When lower data rates are transmitted, the bias voltage is reduced to conserve power. This parameter adaptation directly addresses the technical contradiction by matching the power amplifier's operating conditions to the actual transmission demands.
2Use of energy by moving object
If bias voltage is reduced to conserve power during low-data-rate transmissions, then power consumption decreases, but transmission performance may deteriorate
Solution Approach 1:
The patent employs a feedback mechanism where the system continuously monitors data rate parameters and uses this information to adjust the bias voltage. The feedback loop ensures that the bias voltage is reduced only when the monitored data rate indicates that lower power operation is acceptable. This prevents performance deterioration by maintaining adequate bias voltage when transmission requirements demand it, while enabling power savings when conditions permit.
3Reliability
If fixed high bias voltage is used to maintain performance across all operating conditions, then transmission reliability is ensured, but battery life is reduced
Solution Approach 1:
The system transitions from a static fixed bias voltage approach to a dynamic adaptive approach. By continuously monitoring transmission conditions and adjusting the bias voltage accordingly, the system ensures reliable transmission when needed while conserving battery power during normal operation. This dynamic adaptation directly extends battery life without compromising transmission reliability when high performance is required.
Solution Approach 2:
The system periodically evaluates transmission conditions and adjusts bias voltage in response to changing operational requirements. Rather than maintaining a constant high bias voltage, the system engages in periodic assessment and adjustment, maintaining high performance only during periods when high data rate transmission is actually occurring. This periodic adaptation preserves battery life while ensuring transmission reliability when demanded.
Data Source
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AI summary
Wireless circuitry in an electronic device may contain output power amplifier circuitry for amplifying transmitted radio-frequency signals. The power amplifier circuitry may be powered using a bias voltage. The magnitude of the bias voltage can be selectively reduced to conserve power. Control circuitry can maintain a table of bias voltage settings to use under various conditions. These conditions may include required output powers as determined by link quality, transmission mode status, and required data rates. When link quality is low or when high data rates are required, the bias voltage can be maintained at a relatively high level to ensure that the power amplifier operates linearly and does not exhibit excessive noise. When link quality is high or when data rates are low as with voice calls, the bias voltage can be reduced to conserve power.