MOSFET Receiver Circuit for Ground Noise Isolation
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Solution Overview
Problem
Existing receiver circuits for infrared signals are susceptible to ground noise interference due to shared ground connections, which can lead to incorrect signal decoding and reduced communication reliability, especially in high-speed current mode communication systems.
Innovation Solution
The implementation of a MOSFET and amplifier configuration that maintains a constant voltage at the internal node relative to the ground, combined with separate ground pins and current sources, creates a low impedance node that isolates the receiver from ground noise, ensuring accurate signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a shared ground connection is used in the receiver circuit, then the circuit complexity is reduced, but ground noise interference increases causing incorrect signal decoding
Solution Approach 1:
The ground connection is segmented into separate ground pins (first ground pin and second ground pin) to isolate different functional blocks. The receiver circuit uses the first ground pin while other blocks use the second ground pin, preventing ground noise from affecting signal decoding accuracy.
Solution Approach 2:
A MOSFET is introduced as an intermediary component between the internal node and the receiver input node. The MOSFET's conduction channel acts as a controlled pathway that blocks ground noise while allowing signal transmission, improving decoding accuracy without significantly increasing overall circuit complexity.
2Measurement precision
If ground noise isolation measures are implemented, then signal processing accuracy improves, but device complexity increases
Solution Approach 1:
The circuit is divided into distinct ground domains with separate ground pins for the receiver and other blocks. This segmentation isolates ground noise while maintaining relatively simple circuit architecture, achieving good signal processing accuracy without excessive complexity increase.
Solution Approach 2:
The MOSFET automatically responds to voltage changes at its gate terminal by adjusting its conduction channel conductivity. This self-regulating behavior maintains constant voltage at the internal node without requiring external control circuitry, improving signal accuracy while minimizing added complexity.
3Reliability
If a MOSFET with voltage control is added to maintain constant internal node voltage, then noise immunity improves, but the number of components increases
Solution Approach 1:
The MOSFET serves as an intermediary active component that dynamically controls the connection between the internal node and receiver input node. By adjusting its conduction channel conductivity based on gate voltage, it maintains constant internal node voltage and improves noise immunity while adding only one active component to the circuit.
Solution Approach 2:
The amplifier monitors the voltage at the internal node and provides feedback to the MOSFET gate terminal. This feedback mechanism automatically adjusts the MOSFET's conduction channel conductivity to maintain constant voltage at the internal node, significantly improving noise immunity with minimal additional components.
Data Source
AI summary
A receiver circuit comprising: an input-pin; a receiver-input-node; a ground-pin; an internal-node that is connected to the input-pin; and a MOSFET. The MOSFET has a conduction channel connected in series between the internal-node and the receiver-input-terminal; and a gate terminal, the voltage at which sets the conductivity of the conduction channel. The receiver circuit also includes an amplifier that: has an input terminal that is connected to the internal-node; and provides a voltage control signal to the gate terminal of the MOSFET such that the voltage at the internal-node with respect to the ground-pin is constant.