Universal I/O Output Circuit for Sink-Source Mode Switching
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Solution Overview
Problem
Existing industrial I/O modules require complex wiring and switching mechanisms to switch between sinking and sourcing DC output modes, which can lead to confusion and potential damage from floating power supplies.
Innovation Solution
A DC output circuit with a single low current direction signal controls a pair of transistors to simplify wiring and eliminate the need for high current switching, using a logic circuit to determine whether the output terminal sources or sinks current based on a digital control signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single floating transistor is used to provide both sinking and sourcing DC output circuits, then the versatility of the I/O module is improved, but the device complexity and wiring complexity increase
Solution Approach 1:
The patent divides the single transistor into two separate transistors (first transistor for sourcing mode, second transistor for sinking mode). Each transistor is permanently connected to a dedicated power supply terminal, eliminating the need for complex switching circuitry to reconfigure connections. The logic circuit selectively activates only one transistor at a time based on the desired operating mode.
Solution Approach 2:
The transistors are pre-configured with permanent connections to power supply terminals during manufacturing. The sourcing transistor is permanently connected to the positive terminal while the sinking transistor is permanently connected to the negative terminal, eliminating the need for runtime reconfiguration or floating power supply arrangements.
2Adaptability or versatility
If a floating power supply is used to control the floating transistor, then the dual mode operation is achieved, but the reliability decreases due to susceptibility to damage
Solution Approach 1:
The power supply system is segmented into two independent power supply terminals (positive and negative) with dedicated transistors for each. This eliminates the floating power supply configuration where a single power supply must be reconfigured for different modes, thereby improving reliability by removing the vulnerable floating connection.
Solution Approach 2:
The logic circuit acts as an intermediary that selectively activates either the sourcing or sinking transistor based on the desired operating mode. This mediation eliminates the need for the power supply itself to be reconfigured or floated, protecting the power supply from damage while still enabling dual mode operation.
3Adaptability or versatility
If high current switching is implemented to change operating modes, then the dual mode operation is achieved, but the device complexity and potential for confusion increase
Solution Approach 1:
The patent segments the current paths by providing separate dedicated transistors for sourcing and sinking operations. Each transistor has permanent connections to its respective power terminal, eliminating the need for high-current switching mechanisms and complex terminal reconfiguration. Users simply connect actuators to fixed terminals without needing to understand or perform complex wiring changes.
Solution Approach 2:
The logic circuit serves as a low-current intermediary that controls which transistor conducts based on the desired operating mode. This eliminates the need for high-current switching at the terminals, simplifying the user interface and reducing potential for wiring confusion while maintaining full dual-mode functionality.
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 solution simplifies the wiring of actuators and eliminates the need for high current signal rerouting and floating power supply complexities, providing a reliable and user-friendly universal DC output circuit that can sink or source current depending on a single digital control signal.
Implementation Method 1
a first transistor device connected between the releasable terminal and a terminal receiving a first DC voltage to provide a current flow from the first DC voltage to the releasable terminal when the first transistor device is turned on
Implementation Method 2
a second transistor device connected between the releasable terminal and a terminal receiving a second DC voltage to provide a current flow from the releasable terminal to the second DC voltage source when the second transistor is turned on
Implementation Method 3
a logic circuit providing transistor control signals to the first and second transistor and receiving the given digital control signal and a direction signal indicating whether the releasable terminal should operate as a sourcing DC output or a sinking DC output
Data Source
AI summary
An I/O module for an industrial controller provides single terminal outputs that may either sink or source current. This capability is provided through the use of dedicated sourcing and sinking transistors connected to the terminal and controlled by lockout logic ensuring activation of only the appropriate transistor in the correct phasing for sinking or sourcing operation modes.