RF Power Amplifier Supply Tracking Without RF Isolators
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Solution Overview
Problem
Current mobile communications devices require costly and inflexible RF isolators to match impedance and isolate RF power amplifiers, leading to inefficiencies when supporting multiple frequency bands and varying loads, which increases the bill of materials and reduces amplifier efficiency.
Innovation Solution
An adjustable power supply and monitoring system that adjusts the output voltage of the RF power amplifier in real-time to maintain efficiency by detecting distortion and adjusting the power supply to the minimum required level, eliminating the need for isolators and improving design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an isolator is used to match impedance and isolate the RF power amplifier, then the output impedance is matched and the amplifier is protected from variable loads, but the bill of materials cost increases and design flexibility is reduced
Solution Approach 1:
The patent removes the isolator from the RF power amplifier system. Instead of using a traditional isolator component, the invention implements impedance matching and load isolation through a combination of a matching network and a control system that adjusts amplifier operating parameters in response to load conditions, thereby eliminating the need for the separate isolator component.
Solution Approach 2:
The control system in the patent performs multiple functions: it monitors load conditions, determines appropriate operating parameters, and adjusts the amplifier's operation accordingly. This multi-functional approach replaces what would traditionally require separate components (isolator, matching network, control circuitry), consolidating protection and matching functions into the control system.
2Device complexity
If the isolator is removed to reduce cost and increase flexibility, then the bill of materials cost decreases and design flexibility increases, but the RF power amplifier is exposed to varying loads requiring a large range of output voltages which reduces efficiency
Solution Approach 1:
The patent implements a feedback control system that monitors the actual load conditions presented to the RF power amplifier. Based on this feedback, the control system dynamically adjusts the amplifier's operating parameters (such as bias conditions or operating point) to optimize efficiency for the current load condition, preventing the efficiency losses that would occur with a fixed operating point.
Solution Approach 2:
The invention transitions from a static impedance matching approach (using a fixed isolator) to a dynamic approach where the control system continuously adapts the amplifier's operating parameters in response to changing load conditions. This dynamic adjustment allows the amplifier to maintain high efficiency across a wide range of output voltage requirements without needing excessive voltage headroom.
3Adaptability or versatility
If a fixed supply voltage is used to ensure sufficient output voltage for all load conditions, then the amplifier can handle varying loads, but the efficiency is reduced due to maintaining overhead voltage
Solution Approach 1:
The patent employs dynamic control of the amplifier's operating parameters based on real-time load conditions. Rather than maintaining a fixed supply voltage with overhead capacity, the control system adjusts the operating point dynamically to match the actual power delivery requirements, allowing the amplifier to operate efficiently at lower voltages when full power is not needed while still maintaining the capability to handle peak loads.
Solution Approach 2:
The invention changes the operating parameters of the RF power amplifier dynamically based on load conditions. The control system modifies parameters such as bias voltage, current, or operating point to optimize the balance between output voltage capability and efficiency, allowing the amplifier to adapt its characteristics to match the instantaneous power delivery requirements rather than operating at a fixed, inefficient point.
Data Source
AI summary
An apparatus for amplifying a signal. The apparatus includes an amplifier powered by a power supply, a monitor that monitors an output signal of the amplifier and a controller operative to adjust the power supply if distortion is detected in the output signal of the amplifier by the monitor.