Solid State Power Controller Galvanic Isolation Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid state power controllers (SSPCs) lack an efficient, galvanically isolated discrete output solution, which is crucial for indicating the state of power connection to loads and detecting overcurrent conditions, often relying on electromechanical contactors.
Innovation Solution
A self-locking discrete output circuit within the SSPC that autonomously detects overcurrent and limits output current or interrupts the signal, independent of the SSPC control circuit, using a galvanically isolated connection to provide a signal indicative of the load's power state, reducing the need for multiple signal exchanges and maintaining control terminal voltage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromechanical contactors are used to provide galvanically isolated discrete output, then galvanic isolation is achieved, but device complexity and space requirements increase
Solution Approach 1:
The patent replaces electromechanical contactors with a solid-state discrete output circuit that uses optical coupling (LED and photodetector) to achieve galvanic isolation. This substitutes mechanical moving parts with solid-state components, eliminating the need for contacts while maintaining isolation functionality.
Solution Approach 2:
The patent introduces an optical intermediary (light signal through optical coupling) between the control circuit and the output circuit. This intermediary transfers the discrete output signal while maintaining galvanic isolation, replacing direct electrical contact with optical transmission.
2Measurement precision
If multiple signal exchanges are implemented between discrete output circuit and SSPC control circuit, then signal accuracy is improved, but circuit board space and complexity increase
Solution Approach 1:
The patent combines multiple signal exchange functions into a single integrated discrete output circuit. The circuit performs overcurrent detection, signal generation, and galvanic isolation within one module, eliminating the need for separate signal exchange pathways and reducing circuit board space.
Solution Approach 2:
The discrete output circuit is designed to perform multiple functions simultaneously: providing galvanic isolation, generating discrete output signals, detecting overcurrent conditions, and maintaining control terminal voltage stability. This multi-functionality reduces the overall system complexity and space requirements.
3Measurement precision
If discrete output circuit interacts with SSPC control circuit for overcurrent detection, then detection accuracy is improved, but control terminal voltage stability is affected
Solution Approach 1:
The patent uses optical coupling as an intermediary to separate the overcurrent detection function from the control terminal. The discrete output circuit detects overcurrent through the optical interface without directly interacting with the control terminal, maintaining voltage stability while enabling accurate detection.
Solution Approach 2:
The patent segments the SSPC into functionally independent modules: the control circuit that manages power switching and the discrete output circuit that handles signal generation and overcurrent detection. This segmentation allows each module to operate independently, preventing interference between functions.
Data Source
Figure 1
Figure 2
AI summary
Disclosed is a solid state power controller (10), comprising at least one solid state switching device (18) connected to at least one load to be supplied with power from a power feed line (12) and configured to selectively connect the respective load to the power feed line (12) or to disconnect the respective load from the power feed line (12); at least one SSPC control circuit (20) configured to supply a control voltage to a control terminal (22) of the solid state switching device (18); and a discrete output circuit (100) electrically connected to, and galvanically isolated from, the SSPC control circuit (20) and/or the control terminal (22) of the solid state switching device (18); wherein the discrete output circuit (100) comprises a discrete output terminal (104) and is configured to supply at the discrete output terminal (104) a discrete output signal indicative of the state of the control terminal (22) of the solid state switching device (18), and wherein the discrete output circuit (100) is configured to detect an overcurrent in a circuit (114) connected to the discrete output terminal (104) and to limit an output current and/or interrupt supply of the discrete output signal in case an overcurrent is detected.