Active Optical Cable Current Limiting via Voltage Signaling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Active optical cable assemblies face limitations in providing sufficient electrical power due to ohmic losses and power draw by active optical circuits, leading to voltage drops and potential overcurrent issues, especially over longer lengths, without dedicated electrical conductors for communicating current limit requirements.
Innovation Solution
The solution involves communicating current limit requirements from a host connector to a device connector by setting specific voltage levels on electrical conductors within the active optical cable, allowing the device connector to set a current limit based on received voltage, eliminating the need for additional electrical conductors and preventing overcurrent situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the cable length is increased to extend transmission distance, then the bandwidth and noise performance are improved, but the voltage drop due to ohmic losses increases and power delivery capability deteriorates
Solution Approach 1:
The patent introduces an intermediary signaling mechanism using voltage levels on existing power conductors to communicate current limit information between host and device. This mediator (voltage signal) enables the system to negotiate and enforce current limits without adding physical conductors, thereby resolving the power delivery limitation over long cable lengths.
Solution Approach 2:
The patent changes the parameter being communicated from physical conductor presence to voltage level encoding. By encoding current limit information in voltage levels (e.g., 5V for 900mA, 12V for 1.5A) on existing conductors, the system adapts to long cable lengths by dynamically adjusting current limits based on detected voltage signals, preventing excessive voltage drop while maintaining communication capability.
2Loss of information
If additional electrical conductors are added to communicate current limit requirements, then the current limit communication capability is improved, but the weight, size and cost of the cable assembly increase
Solution Approach 1:
The patent makes the existing electrical conductors serve multiple functions: they simultaneously carry power delivery currents and transmit current limit requirement signals through voltage level encoding. This multi-functionality eliminates the need for dedicated signaling conductors, reducing cable weight, size, and cost while maintaining full current limit communication capability.
Solution Approach 2:
The patent uses voltage levels on existing power conductors as an intermediary to convey current limit information. Instead of adding physical communication conductors, the system embeds communication within the power delivery path using voltage as a mediator, achieving information transfer without increasing cable complexity or weight.
3Power
If the current is not limited by the active optical cable, then the power delivery capacity is improved, but the risk of brown-out and damage to electrical components increases
Solution Approach 1:
The patent implements a feedback mechanism where the host detects voltage levels on conductors to determine current limit requirements, and the device responds by limiting its current draw accordingly. This closed-loop feedback ensures that power delivery remains within safe limits while maximizing available power transfer, preventing brown-outs and component damage without unnecessarily restricting power capacity.
Solution Approach 2:
The patent applies preliminary anti-action by preemptively establishing current limits based on detected voltage signals before overcurrent conditions can occur. The host communicates current limit requirements in advance, and the device configures its current drawing behavior accordingly, preventing harmful overcurrent situations before they arise while still allowing maximum safe power delivery.
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 enables effective power delivery over longer lengths without additional weight, size, or cost, ensuring the connected device receives power within specifications, preventing damage and maintaining data integrity.
Implementation Method 1
communicating current limit requirements from a host circuit to a device circuit by setting voltage levels for a transmitted voltage on one or more electrical conductors
Implementation Method 2
the device connector to set a current limit based on the voltage level. The current limiting circuit limits the amount of current provided to the device in accordance with the detected voltage level
Implementation Method 3
one or more electrical conductors for providing electrical power to a device connected to the second connector
Implementation Method 4
each connector of the active optical cable includes an active optical circuit that converts the electrical data signals present at the connector into optical data signals for transmission over the one or more optical fibers
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Optical cable assemblies with variable output current limits are disclosed. In one embodiment, an active optical cable assembly includes a cable having at least one electrical conductor, a host connector coupled to a first end of the cable, and a device connector coupled to a second end of the cable. The host connector includes a host circuit that determines a current limit of one or more devices coupled to the active optical cable assembly and produces a transmitted voltage in accordance with the current limit on the at least one electrical conductor. The device connector includes a device circuit that detects the transmitted voltage on the at least one electrical conductor and limits a current configured to be provided to a device coupled to the device connector based on the transmitted voltage.