Envelope Tracking Power Supply for Wireless Systems
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Solution Overview
Problem
Conventional wireless systems have low power-conversion efficiency, with only 15% of input power being transmitted, leading to significant power loss and heating in power amplifiers due to inefficient operation.
Innovation Solution
A variable output power supply that tracks the peak voltage envelope of the power amplifier's output using a DC/DC converter with multiple outputs, a switch bank, and an output filter, allowing for rapid changes in output voltage to minimize power amplifier power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a constant DC output voltage is used to power the wireless system, then the power supply operation is simple and stable, but the power amplifier operates inefficiently causing high power loss and heat generation
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant DC voltage power supply to a dynamic variable voltage power supply that continuously adjusts its output voltage to track the envelope of the power amplifier output signal. This dynamic adaptation allows the power supply to match the instantaneous power requirements of the power amplifier, significantly reducing power loss while maintaining operational efficiency.
Solution Approach 2:
The patent implements parameter changes by varying the output voltage parameter of the power supply based on the signal envelope characteristics. The power supply voltage is dynamically adjusted to follow the peak envelope of the power amplifier output, ensuring optimal power delivery across different signal conditions and minimizing energy waste during low-power transmission periods.
2Use of energy by moving object
If a variable voltage output power supply is implemented to track the power amplifier output envelope, then power conversion efficiency is improved, but the power supply structure and control complexity increases
Solution Approach 1:
The patent employs feedback mechanisms where the power supply continuously monitors the power amplifier output signal envelope and adjusts its voltage output accordingly. This closed-loop control ensures that the power supply voltage accurately tracks the signal envelope, optimizing power conversion efficiency while maintaining system stability through real-time adjustments.
Solution Approach 2:
The power supply design incorporates multi-functionality by integrating envelope detection, voltage regulation, and power delivery capabilities into a single system. The power supply not only provides power but also actively tracks and adapts to signal characteristics, reducing the need for separate control circuits and minimizing overall system complexity.
3Loss of energy
If the power supply voltage continuously tracks the signal envelope, then power loss is minimized, but the response time and switching speed requirements increase
Solution Approach 1:
The patent applies preliminary action by having the power supply anticipate and prepare for voltage transitions based on the envelope signal characteristics. The power supply begins adjusting its output voltage in advance of signal peaks and valleys, ensuring smooth tracking without excessive switching activity, thereby reducing power loss while maintaining reasonable response time requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly reduces power loss in wireless systems by efficiently matching the power supply voltage to the signal's envelope, improving power conversion efficiency and reducing waste heat in power amplifiers.
Implementation Method 1
The first input transistor and the second input transistor can generate a primary alternating current through the first transformer winding based on the input voltage and gate driver signals. The second transformer winding can generate a first secondary alternating current based on the primary alternating current.
Implementation Method 2
The alternating current passes the first transistor in a first direction to charge the first capacitor. The alternating current passes the second transistor in a second direction to charge the second capacitor. The first and the second capacitor can store charge based on the first secondary alternating current.
Data Source
AI summary
An envelope tracking power supply has a multiple-output DC/DC converter, having an alternating current generating portion and a full rectifying portion. The alternating current generating portion to receive an input voltage and operate at zero voltage switching. A full rectifying portion includes at least one secondary winding and one voltage doubler output. each having a first transistor, and a second transistor, used as rectifier devices to allow currents to flow bi-directionally and sink and source the currents from and to output capacitors to keep their voltage balance. A switch bank selects a desired voltage from series connected capacitors and connects it to an output filter. The switch bank receives an envelope tracking command from the voltage selector and provides a step voltage to the output. The output voltage is changed at switching speed to track a high bandwidth envelope signal.