Current-Mode Filter Circuit for Low-Voltage Wireless Signal Filtering
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Solution Overview
Problem
Current filter circuits in wireless communication devices, such as active RC filters, require high power supply voltages and occupy significant space due to large capacitors and operational amplifiers, leading to increased power consumption and fabrication costs.
Innovation Solution
The implementation of current-mode amplifiers with a differential architecture that allows for reduced power supply voltage (less than or equal to 0.8 volts) and smaller capacitors, enabling a more compact filter circuit design by using a current-mode amplifier with a first and second inverter coupled to a feedback path, and a passive network like an RC filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active RC filters are used in wireless communication devices, then filtering functionality is achieved, but power supply voltage requirement increases and circuit size increases
Solution Approach 1:
The patent transforms the filter circuit from voltage-mode operation to current-mode operation, fundamentally changing the operating parameter. This allows the filter to function with supply voltages as low as 0.8V or 1.0V, compared to traditional active RC filters that require higher voltages. The current-mode topology with differential amplifiers and inverters enables filtering functionality while operating at reduced voltage levels.
2Reliability
If active RC filters are used in wireless communication devices, then filtering functionality is achieved, but circuit area increases due to large capacitors and operational amplifiers
Solution Approach 1:
By changing from voltage-mode to current-mode operation, the patent enables the use of smaller capacitors that can be implemented as compact integrated structures. The current-mode differential architecture with inverters and feedback paths achieves filtering functionality with reduced component sizes, significantly decreasing the overall circuit area compared to traditional active RC filters.
3Use of energy by moving object
If current-mode amplifiers with differential architecture are used, then power supply voltage is reduced and circuit size is reduced, but circuit complexity increases
Solution Approach 1:
The patent divides the filter circuit into distinct functional blocks: current-mode amplifiers, inverters, and feedback paths. This segmentation allows each component to be optimized independently for low-voltage operation while maintaining overall filtering functionality. The modular differential architecture with separate amplifier and inverter stages achieves voltage reduction through structured complexity.
Data Source
AI summary
Aspects of the present disclosure provide techniques and apparatus for current-mode analog signal filtering. An example filter circuit generally includes a current-mode amplifier. The current-mode amplifier includes a first amplifier including an input and an output; a first inverter including an input coupled to the output of the first amplifier and including an output coupled to a first feedback path, the first feedback path being coupled to a first input of the filter circuit; and a second inverter including an input coupled to the output of the first amplifier.