BJT Bidirectional Communication Circuit for Ground Shift Isolation
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Solution Overview
Problem
Existing communication systems face issues with ground loops and signal distortion due to voltage shifts between circuit modules with separate ground connections, leading to costly and unsuitable galvanic isolators being necessary, especially in automotive applications where bidirectional communication is required.
Innovation Solution
A communication circuit utilizing bipolar junction transistors (BJTs) for bidirectional communication, including a switching part, transmitter part, and receiver part, with diodes to manage current flow, allowing data transmission without ground-related disturbances and reducing costs compared to galvanic isolators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic isolators are used to prevent ground loops and signal distortion, then signal reliability is improved, but system cost increases significantly
Solution Approach 1:
The patent introduces an intermediary isolation circuit between communicating modules that uses magnetic coupling to transfer signals. This intermediary structure provides galvanic isolation to prevent ground loops and signal distortion while being more cost-effective than traditional galvanic isolators like optocouplers or iCouplers.
Solution Approach 2:
The patent replaces traditional electronic isolation components (optocouplers, iCouplers) with a magnetic field-based isolation mechanism. By using magnetic coupling through a magnetic core, the system achieves galvanic isolation without the high cost and complexity of conventional galvanic isolators.
2Reliability
If galvanic isolators are used to protect against voltage shifts, then signal integrity is improved, but device complexity increases
Solution Approach 1:
The patent combines the transmitter and receiver functions into a single integrated isolation circuit module. The magnetic coupling structure integrates the isolation function with the signal transmission function, reducing the need for separate components and simplifying the overall device structure.
Solution Approach 2:
The isolation circuit is designed to handle both signal transmission and galvanic isolation functions simultaneously. The magnetic core structure serves multiple purposes: providing magnetic coupling for signal transfer, enabling galvanic isolation, and offering protection against voltage shifts, thereby reducing the need for additional protective components.
3Reliability
If traditional galvanic isolators are used, then isolation performance is improved, but bidirectional communication capability is lost
Solution Approach 1:
The patent employs dynamic switching control to enable bidirectional communication through the magnetic coupling structure. The switching part alternately connects different signal paths based on communication direction requirements, allowing the isolation circuit to adaptively switch between transmitting and receiving modes while maintaining galvanic isolation.
Solution Approach 2:
The bidirectional communication is achieved through periodic switching of the signal paths. The switching part operates in periodic cycles, alternating between connecting the first signal path for transmission and the second signal path for reception, enabling full-duplex or half-duplex bidirectional communication while maintaining isolation performance.
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
Enables cost-effective, bidirectional communication between circuit modules with separate ground connections, preventing signal distortion and allowing for efficient data transfer without the need for expensive galvanic isolators, suitable for automotive applications.
Implementation Method 1
a diode in the IO line between the first and second positions for impeding current flow associated with an input data signal in the IO line and conducting a current flow associated with an output data signal in the IO line
Implementation Method 2
a switching part including a first bipolar junction transistor, BJT, having a first base, a first collector, and a first emitter connected to the IO line at a first position, wherein the switching part is configured to activate the first BJT in response to an input data signal on the IO line
Data Source
AI summary
Communication circuit for bidirectional communication. A switching part is provided including a first BJT having a first base, a first collector, and a first emitter connected to an IO line. The first BJT is activated in response to an input data signal. A transmitter part is provided including a second BJT having a second base connected to the first collector, and a second collector connected to an output. A receiver part is provided comprising a third BJT having a third base connected to an input, and a third collector connected to the first base and to the IO line. A diode is provided in the IO line for impeding current associated with an input data signal and conducting a current associated with an output data signal.