Envelope Tracker State Mapping for Fast PA Voltage Transitions
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Solution Overview
Problem
Existing envelope tracking systems for power amplifiers in wireless communication systems face inefficiencies due to slow transition times between operational modes, particularly in applications like Wi-Fi, where rapid mode transitions are necessary to manage transmit power effectively.
Innovation Solution
A tracker circuit with a predefined state machine circuit that uses a digital selection signal to manage transitions between operational modes, employing a mapping scheme that includes allowable and forbidden transitions to facilitate faster mode changes, thereby optimizing voltage supply to the power amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional envelope tracking systems are used, then power amplifier efficiency is improved, but transition time between operational modes is excessive
Solution Approach 1:
The patent segments the operational modes into distinct states within a state machine circuit, with predefined transition paths between them. This segmentation allows the system to jump between specific operational modes (e.g., from Wi-Fi mode to cellular mode) through defined state transitions rather than gradual changes, significantly reducing transition time while maintaining power amplifier efficiency.
Solution Approach 2:
The state machine circuit pre-defines all possible operational modes and transition paths between them during system design. This preliminary action enables the tracker circuit to immediately execute pre-planned transitions when mode change commands are received, eliminating the need for real-time calculation and reducing transition latency in applications like Wi-Fi where rapid mode switching is critical.
2Speed
If rapid mode transitions are implemented, then transition speed is improved, but control complexity increases
Solution Approach 1:
The patent introduces a state machine circuit as an intermediary layer between the digital communication interface and the tracker circuit. This intermediary component simplifies the control logic by providing a finite state machine that handles all transition decisions, reducing the complexity burden from the overall system while enabling rapid mode transitions through predefined state changes.
Solution Approach 2:
The state machine circuit uses discrete parameter changes (state transitions) to represent different operational modes. Each state corresponds to a specific operational mode with associated voltage levels and configuration parameters. This parameter-based approach simplifies control complexity by reducing continuous control variables to discrete state transitions, making the system easier to manage while achieving fast switching.
Data Source
AI summary
A tracker circuit configured to provide a variable supply voltage to a power amplifier (PA) circuit is disclosed. The tracker circuit comprises a predefined state machine circuit comprising a plurality of states mapped in accordance with transitions associated with a predefined mapping scheme. In some embodiments, the plurality of states of the state machine circuit identify one or more operational modes associated with the tracker circuit, wherein the one or more operational modes comprises one or more voltage levels respectively associated therewith. In some embodiments, the one or more operational modes comprises at least two active operational modes. In some embodiments, a transition between the one or more operational modes of the tracker circuit is dictated by a decoding of a digital selection signal received from a digital communication interface associated therewith.