Active RF Bypass Circuit With Capacitance Matching
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Solution Overview
Problem
Active circuits face impedance mismatch issues when transitioning to bypass mode, leading to deterioration in signal quality or intensity due to the loading effect of the active element, which increases power consumption unnecessarily.
Innovation Solution
The active circuit incorporates an input unit that adjusts capacitance and a bypass unit with switches to manage signal bypassing, using an equivalent capacitor to cancel the imaginary impedance caused by the active element, thereby maintaining signal quality in bypass mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the active element is disabled to reduce power consumption in bypass mode, then power consumption is reduced, but impedance mismatch occurs causing deterioration in signal quality or intensity
Solution Approach 1:
The patent introduces an input unit with adjustable capacitance as an intermediary component between the signal source and the active element. This input unit acts as a mediator that can be tuned to match the impedance of the signal path when the active element is disabled, thereby preventing impedance mismatch and maintaining signal quality while allowing power consumption to be reduced
Solution Approach 2:
The patent changes the capacitance parameter of the input unit dynamically based on the operating mode. When the active element is disabled for bypass operation, the input unit's capacitance is adjusted to a specific value that compensates for the removed loading effect, thereby maintaining impedance matching. This parameter change allows the system to transition between active and bypass modes without signal quality deterioration
2Reliability
If the active element is designed with matched impedance for active mode, then signal quality is improved during active operation, but the loading effect causes impedance mismatch when bypass mode is enabled
Solution Approach 1:
The patent makes the input unit dynamic by enabling capacitance adjustment based on the operating mode. The input unit transitions from a static impedance-matched design for active mode to a dynamic design where capacitance can be changed to suit bypass mode requirements. This dynamics allows the system to adapt to different operating conditions and maintain impedance matching in both active and bypass modes
Solution Approach 2:
The patent changes the electrical parameters of the input unit, specifically the capacitance value, to adapt to different operating modes. When switching from active to bypass mode, the capacitance parameter is adjusted to compensate for the removal of the active element's loading effect, thereby maintaining impedance matching with the signal path across different operational states
Data Source
AI summary
An active circuit includes an active element, an input unit, and a bypass unit. The active element is coupled to an output terminal of the active circuit for outputting an output signal. The input unit is coupled to an input terminal of the active circuit, and is coupled to an input terminal of the active element through a node. The input unit adjusts a capacitance value of the input unit according to a first control signal. The bypass unit is coupled to an output terminal of the input unit through the node, and is coupled to the output terminal of the active circuit. The bypass unit turns on or off a signal bypassing path according to a second control signal.