Envelope Tracking Circuit With Buck-DAC Alignment for RF Power Amplifiers
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Solution Overview
Problem
Existing power amplifier systems face inefficiencies in managing power consumption and signal amplification, particularly in radio frequency (RF) systems, as they require precise control of supply voltage to match the envelope of the RF signal, which current techniques fail to address effectively.
Innovation Solution
A power amplifier system incorporating a buck converter and a push-pull digital-to-analog converter (DAC) to generate a supply voltage that adjusts based on the RF signal's envelope, using a combination of digital filtering, shaping, and delaying to control the supply voltage, reducing design complexity and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking is implemented to reduce power consumption, then power efficiency is improved, but device complexity increases due to the need for additional control circuits
Solution Approach 1:
The patent combines the buck converter and DAC module into an integrated envelope tracker circuit that jointly controls the power amplifier supply voltage. The buck converter generates the supply voltage while the DAC module adjusts its magnitude based on the RF signal envelope, merging voltage generation and control functions into a unified system that reduces overall complexity compared to separate control circuits.
Solution Approach 2:
The envelope tracker circuit performs multiple functions: it generates the power amplifier supply voltage through the buck converter, adjusts the voltage magnitude via the DAC module based on envelope detection, and provides dynamic power management. This multi-functional integration eliminates the need for separate dedicated control circuits for each function.
2Use of energy by moving object
If precise supply voltage control is implemented to match RF signal envelope, then power efficiency is improved, but design complexity increases due to additional filtering and delay requirements
Solution Approach 1:
The patent extracts the filtering and delay functions from the analog domain and implements them digitally within the DAC module. The DAC module receives digital envelope data, applies necessary filtering and delay processing in the digital domain, and generates the appropriate control signals to adjust the buck converter output voltage, thereby eliminating complex analog filtering and delay circuits.
Solution Approach 2:
The patent replaces analog filtering and delay circuits with digital signal processing implemented in the DAC module. By using digital algorithms for envelope filtering and time-delay adjustment, the system achieves precise voltage control without requiring physical analog filters and delay elements, significantly reducing design complexity.
3Measurement precision
If analog filters and delay elements are used to control supply voltage, then voltage precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent substitutes analog filtering and delay circuits with digital signal processing implemented in the DAC module. The DAC module processes digital envelope data through digital filtering algorithms and applies digital delay as needed, then generates precise control signals for the buck converter. This digital approach achieves the same voltage precision as analog circuits while eliminating the need for physical analog filters and delay elements.
Solution Approach 2:
The DAC module serves as an intermediary between the digital envelope detector and the analog buck converter. It converts digital envelope data into precise analog control signals through digital-to-analog conversion, applying necessary filtering and delay processing in the digital domain before generating the final control voltage. This intermediary approach maintains voltage precision while avoiding direct use of complex analog filtering circuits.
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
This solution enhances power efficiency and reduces design complexity by aligning the outputs of the buck converter and DAC, eliminating the need for analog filters and delay elements, thereby optimizing power consumption and signal amplification in RF systems.
Implementation Method 1
a buck converter configured to generate a buck voltage from a battery voltage
Implementation Method 2
a digital-to-analog converter (DAC) module configured to adjust a magnitude of the buck voltage based on the envelope of the RF signal
Data Source
AI summary
Apparatus and methods for envelope tracking systems are provided. In certain configurations, an envelope tracking system includes a digital filter that generates a filtered envelope signal based on a digital envelope signal representing an envelope of a radio frequency signal, a buck converter controllable by the filtered envelope signal and including an output electrically connected to a power amplifier supply voltage, a digital-to-analog converter module including an output electrically connected to the output of the buck converter and that provides an output current, and a digital shaping and delay circuit configured to generate a shaped envelope signal based on shaping the filtered envelope signal. The shaped envelope signal controls a magnitude of the output current, and the digital shaping and delay circuit controls a delay of the shaped envelope signal to align the output of the digital-to-analog converter module and the output of the buck converter.