AC-Coupled Data Transmission Circuit DC Balance Control
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Solution Overview
Problem
Conventional AC-coupled data transmission systems require a period for DC balance adjustment and SYNC pattern transmission, leading to increased circuit area, power consumption, and overhead, especially in bidirectional communication systems.
Innovation Solution
The system employs a serializer, DC balancing encoder, and transmission/reception mode switching unit to maintain a constant voltage amplitude and eliminate the need for resistance circuits in receivers by using switches to set an intermediate electric potential on the transmission line, allowing immediate data transmission and reception without SYNC pattern transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional AC-coupled transmission system uses resistance circuits for DC balance adjustment and SYNC pattern transmission, then communication stability is improved, but circuit area and power consumption increase
Solution Approach 1:
The patent extracts and eliminates the resistance circuits from the receiver side by implementing DC balance adjustment functionality in the transmitter only. The transmitter uses switches to adjust the DC balance of transmitted signals, removing the need for corresponding resistance circuits in the receiver, thereby reducing overall circuit area while maintaining communication stability
Solution Approach 2:
The transmitter is designed to perform multiple functions: data transmission, DC balance adjustment, and intermediate electric potential generation. By consolidating these functions in the transmitter, the system eliminates the need for separate resistance circuits in the receiver, achieving multi-functionality that reduces circuit complexity and area
2Reliability
If resistance circuits are used for DC balance adjustment, then communication stability is improved, but power consumption increases
Solution Approach 1:
The patent removes resistance circuits from the receiver side, extracting the DC balance adjustment functionality to the transmitter only. Since resistance circuits are power-consuming components, their removal from the receiver directly reduces overall system power consumption while the transmitter maintains communication stability through active DC balance control
Solution Approach 2:
The transmitter performs DC balance adjustment on its own transmitted signals using switches and capacitors, making the system self-sufficient for DC balance control. This self-service approach eliminates the need for power-consuming resistance circuits in the receiver, as the transmitter independently manages the DC characteristics of the communication link
3Reliability
If SYNC pattern transmission is used for DC balance adjustment, then communication stability is improved, but communication overhead increases
Solution Approach 1:
The patent implements preliminary DC balance adjustment by generating an intermediate electric potential in the transmitter before actual data transmission begins. This preliminary action establishes the correct DC operating point and capacitive charging state, eliminating the need for subsequent SYNC pattern transmission and reducing communication overhead
Solution Approach 2:
The system maintains continuous useful action by establishing the intermediate electric potential and DC balance condition before data transmission, ensuring that the communication channel is immediately ready for productive data transfer. This continuous preparation eliminates idle SYNC pattern transmission periods, maintaining uninterrupted useful communication
4Reliability
If resistance circuits are provided in both transmitter and receiver, then impedance matching is improved, but device complexity increases
Solution Approach 1:
The patent extracts the impedance matching and DC balance adjustment functionality from the receiver side and consolidates it in the transmitter. The transmitter uses switches and capacitors to provide the necessary impedance matching and DC control, removing the need for complex resistance circuits in the receiver and thereby reducing overall device complexity
Solution Approach 2:
The system changes the operational parameters by using switches and capacitors instead of resistance circuits for DC balance adjustment. This parameter change allows the transmitter to control the DC characteristics and impedance of the transmission line dynamically, eliminating the need for corresponding resistance circuits in the receiver and simplifying the overall device architecture
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 approach reduces the time to stabilize communication, decreases power consumption, and eliminates the need for resistance circuits, thereby minimizing circuit area and electromagnetic noise.
Implementation Method 1
Capacitors C are connected in series on the transmitter output terminal sides and receiver input terminal sides of respective lines of the transmission line L. These capacitors C are used for AC coupling that blocks a Direct Current (DC) component contained in serial data being transmitted via the transmission line L.
Implementation Method 2
The resistance values of the resistors R1 and R2 are all set to, for example, 50 Ω, and are matched with the characteristic impedance on the transmission line L.
Data Source
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AI summary
Disclosed herein are a data transmission circuit and a data communication device that transmit data using an Alternating Current (AC)-coupled transmission line. The data transmission circuit includes a data transmission unit for transmitting data via a transmission line having a single AC-coupled line or a plurality of AC-coupled lines. When transmitting data, the data transmission unit transmits the data via the transmission line by sequentially setting a first electric potential corresponding to the data and a second electric potential different from the first electric potential. When transitioning from data transmission mode to an idle state, the data transmission unit sets an intermediate electric potential between the first electric potential and the second electric potential.