Multi-Level Step-Up/Down Converter for Low Ripple RF Power
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Solution Overview
Problem
Conventional DC-DC converters for RF applications face challenges in reducing output ripple, maintaining high bandwidth, and efficiency, especially in envelope tracking and polar modulation, due to high switching frequencies and interference with RF signals.
Innovation Solution
A multi-level Step-Up/Down converter architecture combining charge-pump and Step-Down converter technologies, utilizing a charge pump to generate PWM signals with reduced switching amplitude, allowing for smaller ripples and lower electrical stress on components, and incorporating a low-pass filter to smooth the output signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high switching frequency is used to reduce output ripple, then output ripple is reduced, but efficiency decreases and interference with RF signals increases
Solution Approach 1:
The patent segments the single high-frequency switching operation into multiple lower-frequency switching operations. The multi-level converter divides the voltage conversion process into several stages, each operating at a lower switching frequency, thereby reducing overall ripple while maintaining efficiency and avoiding RF interference.
Solution Approach 2:
The patent employs periodic switching actions at optimized frequencies for each stage. By carefully designing the switching periods and duty cycles of multiple stages, the converter achieves ripple cancellation effects while operating at lower frequencies that do not interfere with RF signals.
2Object-generated harmful factors
If high switching frequency is used to reduce output ripple, then output ripple is reduced, but interference with RF signals increases
Solution Approach 1:
The patent segments the voltage conversion into multiple stages operating at different frequencies, preventing any single stage from generating high-frequency interference that would affect RF signals, while still achieving low output ripple through coordinated operation.
3Speed
If small inductor is used to achieve high bandwidth, then bandwidth is increased, but output ripple increases
Solution Approach 1:
The patent divides the filtering function across multiple stages, each with its own inductor and capacitor. This segmentation allows each stage to use smaller components for high bandwidth while the cumulative effect of multiple stages maintains low output ripple.
Solution Approach 2:
The patent adds temporal dimension to the filtering process by using multi-stage conversion with different switching frequencies. This allows the system to achieve both high bandwidth and low ripple by processing the signal through multiple time-synchronized stages rather than relying on a single large inductor.
4Device complexity
If standard Step-Down converter is used, then simplicity is maintained, but output ripple is high and bandwidth is limited
Solution Approach 1:
The patent segments the conversion process into multiple coordinated stages, achieving low ripple and high bandwidth performance that would be difficult to obtain with a single-stage converter, while maintaining reasonable complexity through modular design.
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
The solution achieves lower ripples, higher bandwidth, and reduced energy loss, enabling efficient power supply modulation for RF amplifiers with minimal interference and the ability to output voltages beyond the input voltage, improving efficiency and spectral performance.
Implementation Method 1
A multi-level Step-Up/Down converter architecture combining charge-pump and Step-Down converter technologies, utilizing a charge pump to generate PWM signals with reduced switching amplitude
Implementation Method 2
incorporating a low-pass filter to smooth the output signal
Data Source
AI summary
A voltage converter device converts an input signal having a given input voltage value into an output signal having an output voltage different from the input voltage. The device comprises a main module, arranged between an input terminal and a first circuit node, The device is adapted to output at the first circuit node a pulse-width-modulated signal switching between a first voltage value and a second voltage value, defining a switching range, by switching successively between a first mode of operation and a second mode of operation. The switching range of the pulse width modulation has an amplitude, calculated as the absolute difference between the first and the second voltage value, inferior or equal to half the input voltage.