Dual-Input Envelope Tracking IC for Delay-Aligned RF Power Amplifiers
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Solution Overview
Problem
Existing envelope tracking (ET) amplifier apparatuses in mobile communication devices suffer from degraded linearity and efficiency due to inherent processing and propagation delays, leading to misalignment between the time-variant voltage envelope and the power envelope, which compromises the overall performance.
Innovation Solution
A dual-input envelope tracking (ET) integrated circuit (ETIC) is introduced, featuring an ET voltage circuit and a target voltage processing circuit, along with a control circuit that determines parameters based on the ET power range to optimize performance across a wide range of modulation bandwidths, thereby improving linearity and efficiency by aligning the ET voltage envelope with the power envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking is used to improve power amplifier efficiency, then power consumption and thermal dissipation are reduced, but processing and propagation delays cause misalignment between voltage envelope and power envelope
Solution Approach 1:
The patent applies preliminary action by predicting future voltage envelope values based on historical data and current input signals. The predictor circuit generates predicted voltage values in advance before they are actually needed, compensating for the processing delays in the envelope tracking circuit. This allows the system to pre-position the voltage envelope to match future power requirements, resolving the timing misalignment caused by processing delays.
Solution Approach 2:
The patent implements feedback mechanisms where the actual voltage envelope and power amplifier output are monitored and fed back to the predictor and controller circuits. This feedback loop allows the system to continuously adjust predictions and corrections based on actual performance, ensuring that the voltage envelope remains aligned with the power envelope despite varying operating conditions and delays.
2Power
If sophisticated power amplifiers are employed to increase output power, then higher data rates are achieved, but power consumption and thermal dissipation increase
Solution Approach 1:
The patent applies dynamics by making the supply voltage to the power amplifier time-variant rather than constant. The envelope tracking circuit dynamically adjusts the supply voltage to match the instantaneous power requirements of the amplifier. This allows the amplifier to operate at high output power when needed while consuming less average power, as the supply voltage is reduced during low-signal periods. The dynamic voltage adjustment enables the system to achieve high peak power output without proportionally increasing average power consumption.
3Use of energy by moving object
If time-variant voltages are used to track power envelope, then amplifier efficiency is improved, but processing delays degrade tracking accuracy
Solution Approach 1:
The predictor circuit performs preliminary action by calculating predicted voltage envelope values in advance, compensating for processing delays. The system uses historical voltage data and current input signals to forecast future voltage requirements, generating predicted values before the actual tracking point. This preliminary prediction ensures that when the voltage is actually applied, it corresponds to the correct instantaneous power level, maintaining tracking accuracy despite processing delays.
Solution Approach 2:
The patent applies parameter changes by modifying the voltage envelope parameters (amplitude, timing) based on predicted future conditions and actual measured performance. The controller adjusts the voltage envelope parameters dynamically to compensate for processing delays and maintain accurate tracking. This involves changing the timing offset and amplitude scaling factors to optimize the relationship between the voltage envelope and power envelope under varying operating conditions.
Data Source
AI summary
A dual-input envelope tracking (ET) integrated circuit (ETIC) and related apparatus are provided. The dual-input ETIC includes an ET voltage circuit configured to generate an ET voltage based on an ET voltage and a first set of parameters. The ET voltage may be provided to a power amplifier circuit(s) for amplifying a radio frequency (RF) signal(s) in an ET power range. The dual-input ETIC also includes a target voltage processing circuit configured to generate the ET target voltage based on a second set of parameters. The dual-input ETIC further includes a control circuit configured to determine the first set of parameters and the second set parameters based at least on the ET power range of the power amplifier circuit(s). As such, it may be possible to optimize the dual-input ETIC performance in a wide-range of modulation bandwidth, thus helping to improve linearity and efficiency of the power amplifier circuit(s).