Envelope Tracking Voltage Compensation for RF Ripple Cancellation
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Solution Overview
Problem
Existing transmission circuits face challenges in maintaining alignment between the time-variant ET voltage and the time-variant voltage envelope, leading to inefficiencies and linearity issues in power amplifiers, especially in millimeter wave spectrums.
Innovation Solution
A transceiver circuit is configured to add a compensation term to the modulated target voltage to cancel the ripple in the modulated voltage, thereby improving the alignment and overall RF performance of the transmission circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If envelope tracking is used to improve power amplifier efficiency and linearity, then power management performance is improved, but voltage ripple is introduced due to inductive impedance interaction
Solution Approach 1:
The patent converts the harmful voltage ripple caused by inductive impedance interaction into a beneficial alignment mechanism. By intentionally introducing a compensating ripple through the envelope tracking circuitry that is phase-aligned with the power amplifier's current waveform, the previously harmful ripple becomes a useful component that improves overall system performance. This transforms the adverse effect of inductive impedance into a positive contribution to efficiency and linearity.
Solution Approach 2:
The patent modifies the voltage waveform parameters by adding a compensation term that changes the amplitude and phase characteristics of the envelope tracking voltage. This parameter adjustment allows the system to optimize the alignment between voltage and current waveforms, thereby improving power amplifier efficiency and reducing distortion without eliminating the underlying inductive impedance.
2Ease of manufacture
If group delay and impedance mismatch are present in the envelope tracking circuit, then circuit implementation is simplified, but alignment between ET voltage and voltage envelope deteriorates
Solution Approach 1:
The patent employs feedback mechanisms within the envelope tracking circuitry to dynamically adjust the compensation term based on the actual operating conditions. By continuously monitoring the alignment between the ET voltage and the voltage envelope, the system can compensate for group delay and impedance mismatch effects, maintaining optimal performance without requiring precise manual calibration or complex impedance matching networks.
Solution Approach 2:
The patent applies preliminary compensation by pre-calculating and embedding correction terms in the envelope tracking voltage waveform before it reaches the power amplifier. This preliminary action accounts for anticipated group delay and impedance effects, ensuring proper alignment is achieved without requiring complex real-time adjustment circuits or precise component matching.
Data Source
AI summary
Voltage ripple cancellation in a transmission circuit is provided. The transmission circuit includes a power amplifier circuit that amplifies a radio frequency (RF) signal based on a modulated voltage and a modulated current. Specifically, the modulated current is generated inside the power amplifier circuit based on a time-variant input power of the RF signal, and the modulated voltage is generated by an envelope tracking integrated circuit (ETIC) based on a time-variant target voltage and provided to the power amplifier circuit via a conductive path. Collectively, the ETIC and the conductive path present a total inductive impedance that interacts with the modulated current to cause a ripple in the modulated voltage at the power amplifier circuit. Herein, a transceiver circuit is configured to add a compensation term to the modulated target voltage to cancel the ripple in the modulated voltage to thereby improve overall RF performance of the transmission circuit.