Wireless Output Power Control via Open-Loop Closed-Loop Transition
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Solution Overview
Problem
Existing wireless communications circuitry in portable electronic devices faces challenges in accurately controlling radio-frequency output powers, particularly due to inaccuracies in power measurements at low powers and difficulties in transitioning between closed-loop and open-loop control regimes, leading to potential output power inaccuracies and service disruptions.
Innovation Solution
The implementation of a control circuitry that smoothly transitions between open-loop and closed-loop control regimes by using modified open-loop and closed-loop schemes, incorporating power measurements and known power offset information, and employing linear or monotonically varying transition zone curves to ensure accurate output power adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop control is used for output power control, then measurement accuracy is improved, but it becomes inapplicable at low power levels where power detector measurements are inaccurate
Solution Approach 1:
The patent divides the output power control range into multiple segments: a first output power range where closed-loop control is used, and a second output power range where open-loop control is used. This segmentation allows each control method to operate in its optimal range, resolving the contradiction between measurement accuracy and applicability across all power levels.
Solution Approach 2:
The patent dynamically transitions between closed-loop and open-loop control methods based on the current output power level. When the output power exceeds a threshold, closed-loop control is activated; when it falls below the threshold, open-loop control takes over. This dynamic switching ensures both measurement accuracy when applicable and versatility across all power ranges.
2Device complexity
If open-loop control is used at low power levels, then control simplicity is improved, but output power accuracy deteriorates due to frequency dependence
Solution Approach 1:
The patent introduces feedback mechanisms into the open-loop control path by using power detector measurements to generate feedback signals that adjust the output power. This hybrid approach maintains the simplicity of open-loop control while incorporating feedback to compensate for frequency-dependent inaccuracies, thereby improving output power accuracy without significantly increasing complexity.
3Adaptability or versatility
If transitions between open-loop and closed-loop control regimes are implemented, then adaptability across power ranges is improved, but service disruptions may occur during transitions
Solution Approach 1:
The patent prepares for transitions between control regimes by establishing a threshold value in advance. Before switching from open-loop to closed-loop control, the system monitors when the output power approaches this threshold and initiates preparatory adjustments. This preliminary action ensures smooth transitions without abrupt changes that could cause service disruptions.
Solution Approach 2:
The patent implements cushioning measures during control regime transitions by using overlapping control regions and gradual parameter adjustments. When transitioning between open-loop and closed-loop control, the system maintains both control mechanisms temporarily and gradually shifts dominance from one to the other, preventing sudden changes that could disrupt service.
4Device complexity
If frequency-dependent open-loop control is used, then device complexity is reduced, but output power control accuracy worsens
Solution Approach 1:
The patent changes the control parameters dynamically based on the operating conditions. In open-loop mode, the system uses frequency-dependent parameter adjustments to improve accuracy. In closed-loop mode, it uses feedback-based parameter adjustment. This parameter changing strategy allows the system to maintain lower complexity while achieving better output power control accuracy across different operating conditions.
Data Source
AI summary
Wireless circuitry in an electronic device may contain radio-frequency transceiver circuitry and power amplifier circuitry that transmits radio-frequency signals through an antenna. A tap and power detector that are interposed in the radio-frequency signal path between the power amplifier circuitry and the antenna may be used to make output power measurements. Control circuitry may control the wireless circuitry in an open-loop control regime in which output power adjustments are based on a requested power without using the output power measurements. The control circuitry may also control the wireless circuitry in a closed-loop control regime in which the output power measurements serve as a source of real time feedback to determine whether to increase or decrease the output power. The output power may be controlled using linear transition zone power control curves in a transition zone between the open-loop regime and the closed-loop regime.