RFID Power Amplifier with Reconfigurable Sin-Square Waveforms
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Solution Overview
Problem
Existing digital power amplifiers for RFID antennas face inefficiencies in power transfer and require external passive filtering to manage harmonics, which becomes less efficient at lower power levels.
Innovation Solution
A digital power amplifier with switching means that can switch 2*W driver blocks into a none-contributing mode, reducing power transfer without altering the digital wave-forming bit combination, and utilizing a memory with stored wave-forming bit combinations and clip-values to stepwise adjust output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If direct sin wave synthesis is used for power amplification, then efficiency at high power is improved, but efficiency at lower power levels deteriorates
Solution Approach 1:
The power amplifier is divided into multiple parallel driver blocks (2W blocks) that can be independently controlled. Each driver block contributes a portion of the total output current, allowing the system to segment the power output and selectively activate only the necessary number of blocks based on the required power level, thereby maintaining efficiency across different power ranges.
Solution Approach 2:
The system dynamically adjusts the number of active driver blocks based on the required output power level. By switching blocks between active and inactive states, the amplifier adapts its configuration to match the power demands, transitioning from high-power sinusoidal mode to lower-power modes with fewer active blocks, thus maintaining optimal efficiency across varying power levels.
2Ease of manufacture
If square wave generation is used for power amplification, then ease of generation is improved, but power efficiency deteriorates due to filtering requirements
Solution Approach 1:
The system changes the waveform parameter dynamically based on power level. At high power levels, it generates sinusoidal waveforms for maximum efficiency. At lower power levels, it transitions to trapezoidal and eventually square waveforms, which are easier to generate digitally. This parameter change allows the system to prioritize ease of generation when power efficiency is less critical.
Solution Approach 2:
The waveform shape is dynamically adjusted based on the operating power level. The system transitions from sinusoidal at high power to trapezoidal at medium power, and to square wave at low power. This dynamic adaptation allows the system to use the most efficient waveform for each operating condition.
3Loss of energy
If all driver blocks remain active for power adjustment, then power transfer efficiency is improved, but device complexity increases due to control requirements
Solution Approach 1:
The control section is segmented to independently control each driver block. By dividing the control function into separate control signals for each block, the system can selectively activate or deactivate individual blocks based on power requirements, simplifying the overall control logic while maintaining efficient power transfer through selective block activation.
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 enables efficient power transfer and adjustment at high power amplitudes without external filtering, transitioning to more trapezoidal and eventually square waveforms at lower powers, maintaining low harmonic energy content.
Implementation Method 1
a magnetic field of the power device to charge the two earphones wireless
Implementation Method 2
feed the substantial sinusoidal output current with a transmission resonance frequency to the RFID antenna
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A digital power amplifier (4, 5) to drive an RFID antenna (6, 7) with an antenna signal (AS) of a substantial sinusoidal output current which digital power amplifier (4, 5) comprises: an integrated circuit (3) with a first transmission output pin (8) and a second transmission output pin (9) to provide an output signal (OS); an adaption circuit (12, 13) of discrete components connected to the first and second transmission output pin (8, 9) to adapt the output signal (OS) and feed the substantial sinusoidal output current with a transmission resonance frequency to the RFID antenna (6, 7); a digital control section (14) with a number of W wave-forming contacts (15) to output a digital wave-forming bit combination with a clock frequency M-times the transmission resonance frequency; a number of 2*W driver blocks (18) each connected with a first contact (19) to one of the wave-forming contacts (15) and a number of W of them connected with a second contact (20) to the first transmission output pin (8) and the other number of W of them connected with their second contact (20) to the second transmission output pin (9), which driver blocks (18) are built to provide charge increments for the substantial sinusoidal output current (I) to the first and second transmission output pin (8, 9), wherein the digital control section (14) comprises: switching means (27, 28) built to switch at least four of the 2*W driver blocks (18) from a contributing mode into a none-contributing mode, in which none-contributing mode the driver block (18) does not contribute charge for an increment to the output current, to adjust the amplitude and/or the waveform of the output signal (OS).