Transmission Gate Control for Low-Distortion MOSFET Signal Transfer
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Solution Overview
Problem
Conventional transmission gates introduce distortion in signal transmission due to voltage-dependent resistance variations, leading to suboptimal performance when connected to finite load impedance.
Innovation Solution
The electric circuitry employs a control circuit to manage the conductivity of a first n-channel MOSFET and a second p-channel MOSFET within the transmission gate, using threshold voltage comparisons to optimize transistor operation and minimize distortion by switching between conductive and non-conductive states based on input signal levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional transmission gate with fixed control signals is used, then simple control is achieved, but distortion occurs due to voltage-dependent resistance variations
Solution Approach 1:
The patent applies dynamics by transitioning from fixed control signals to dynamic control signals that adapt to the input voltage level. The control circuit generates control signals CS1 and CS2 that vary dynamically based on the instantaneous voltage at node A, enabling the transmission gate to maintain optimal resistance characteristics across different operating conditions and reduce signal distortion.
Solution Approach 2:
The patent implements parameter changes by modifying the control signal voltage levels based on the input signal characteristics. The control circuit changes the voltage parameters of control signals CS1 and CS2 in response to different input voltage levels, thereby adjusting the conductivity of the transistors to minimize distortion while maintaining signal transmission accuracy.
2Adaptability or versatility
If n-channel and p-channel MOSFETs are used in parallel, then conduction is achieved across entire voltage range, but resistance variations cause distortion
Solution Approach 1:
The patent applies local quality by making each transistor's control independent and optimized for specific voltage ranges. Instead of treating the transmission gate uniformly, the control circuit provides differentiated control signals to the n-channel and p-channel MOSFETs based on the local voltage conditions, allowing each transistor to operate in its optimal conduction region and reducing overall distortion.
Solution Approach 2:
The patent uses dynamics to enable the transmission gate to adapt its resistance characteristics dynamically across different voltage ranges. The control circuit continuously adjusts the control signals based on the instantaneous voltage level, allowing the gate to maintain low distortion performance whether operating at negative, zero, or positive voltage levels.
3Reliability
If control signals are inverted for complementary transistors, then proper switching is achieved, but distortion peaks occur at threshold voltages
Solution Approach 1:
The patent implements feedback by using the input voltage at node A directly to generate the control signals. The control circuit monitors the instantaneous voltage level and uses this information to adjust the control signals CS1 and CS2, creating a feedback mechanism that compensates for the distortion that would otherwise occur at threshold voltage transitions.
Solution Approach 2:
The patent applies parameter changes by continuously adjusting the control signal voltage levels based on the input signal characteristics. Instead of using fixed inverted control signals, the control circuit modifies the voltage parameters of CS1 and CS2 in real-time to maintain optimal transistor operation and minimize distortion peaks during switching transitions.
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 configuration significantly reduces distortion in the output signal, flattening peaks in the transfer function and minimizing total harmonic distortion, particularly when the transmission gate is loaded with finite impedance, thereby enhancing signal quality.
Implementation Method 1
The control circuit is configured to generate the first and second control signal in dependence on a voltage level of the input signal to control the conductivity of the first and second transistor
Data Source
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AI summary
An electric circuitry (10) for signal transmission comprises a transmission gate (100) having an input node (A) to apply an input signal (VIN). The transmission gate (100) includes a first transistor (110) having an electric conductive channel of a first type of conductivity and a second transistor (120) having an electric conductive channel of a second type of conductivity. The electric circuitry (10) comprises a control circuit (200) to control the signal transmission of the transmission gate (100). The control circuit (200) is configured to generate a first and second control signal (CS1, CS2) to control the conductivity of the first and second transistor (110, 120) in dependence on a voltage level of the input signal (VIN).