RFID Digital Power Amplifier With Sinusoidal Output and Fewer Filters
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Solution Overview
Problem
High-voltage digital power amplifiers used in RFID devices have a large number of discrete components in their adaptation circuits, increasing size and manufacturing costs, and these components cannot be integrated into the amplifier due to high inductive reactance and capacitance requirements.
Innovation Solution
A digital power amplifier design with an integrated circuit that includes a digital control section with wave-forming contacts to output digital wave-forming bit combinations, driving driver blocks to provide increments of sinusoidal output current directly to the transmission output pins, eliminating the need for external filter means and reducing the number of discrete components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If external filter means and resonance means with discrete components are used to generate sinusoidal output current, then the output signal quality meets spurious emission levels, but the number of discrete components increases device complexity and manufacturing cost
Solution Approach 1:
The patent merges the filter means and resonance means into a single integrated resonance circuit that is directly connected to the output of the high-voltage amplifier. This consolidation reduces the number of discrete components while maintaining the necessary signal conditioning functionality to meet spurious emission levels.
Solution Approach 2:
The resonance circuit serves multiple functions simultaneously: it acts as both a filter to suppress spurious emissions and as a resonance means to generate the sinusoidal output current at the desired frequency. This multi-functionality reduces the overall component count while achieving the required output signal quality.
2Object-generated harmful factors
If inductors with high inductive reactance and capacitors with high capacity are used in filter means, then the sinusoidal output current is achieved, but the components cannot be integrated into the amplifier circuit
Solution Approach 1:
The patent changes the electrical parameters of the resonance circuit components to values that can be achieved with integrated circuit technology. By selecting inductance and capacitance values that are compatible with on-chip implementation, the resonance means can be fabricated as part of the amplifier itself rather than requiring external discrete components.
3Power
If multiple discrete components are used in adaption circuit, then the amplifier can drive RFID antenna with maximal power, but the amplifier size and manufacturing cost increase
Solution Approach 1:
The adaption circuit components are merged with the amplifier structure, with the resonance circuit being directly integrated into the amplifier chip. This integration maintains the ability to deliver maximal power to the RFID antenna while significantly reducing the overall device size by eliminating the need for external discrete components.
Data Source
Figure 1~2
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AI summary
A Digital power amplifier (13) to drive an RFID antenna (10) with a substantial sinusoidal output current (I) which digital power amplifier (13) comprises: an integrated circuit (IC2) with a first transmission output pin (15) and a second transmission output pin (16) to provide an output signal (17); an adaption circuit (14) of discrete components (C2a, C2b) connected to the first and second transmission output pin (15, 16) to adapt the output signal (17) and feed the substantial sinusoidal output current (1) with a transmission resonance frequency to the RFID antenna (10), wherein the integrated circuit (IC2) comprises: a digital control section (19) with a number ofN wave-forming contacts (20) to output a digital wave-forming bit combination of N bits with a clock frequency M-times the transmission resonance frequency; a number ofN driver blocks (21) each connected with a first contact (22) to one of the wave-forming contacts (20) and a number of N/2 of them connected with a second contact to the first transmission output pin (15) and the other number of N/2 of them connected with their second contact to the second transmission output pin (16), which driver blocks (21) are built to provide increments of the substantial sinusoidal output current (I) to the first and second transmission output pin (15, 16).