Multi-Channel Solid-State Relay Isolation to Prevent Ground Leakage
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Solution Overview
Problem
Multi-channel solid-state relay circuits face issues with unintended activation due to current flow through a common ground, leading to inefficient designs with multiple isolated gate drive power supplies, which increase circuit area and cost.
Innovation Solution
A multi-channel solid-state relay circuit using a single isolated power supply and a multi-channel isolator circuit, coupled with diodes to block current flow and high-impedance voltage translation circuits to prevent leakage currents, ensuring reliable operation without unintended activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple isolated gate drive power supplies are used to drive multi-channel solid-state relays, then reliability is improved by preventing unintended activation, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple isolated gate drive power supplies into a single isolated power supply that serves all channels. The isolator circuit provides galvanic isolation between the control circuit and multiple output channels, eliminating the need for separate isolated power supplies for each channel while maintaining reliability.
Solution Approach 2:
The single isolated power supply is designed to universally drive multiple channels of solid-state relays. The isolator circuit distributes the isolated power supply output to multiple output switches, allowing one power supply to perform the function that previously required multiple separate power supplies.
2Reliability
If multiple isolated gate drive power supplies are used for each channel, then reliability is improved, but circuit area increases
Solution Approach 1:
The patent consolidates multiple isolated power supplies into a single isolated power supply that serves all channels through the isolator circuit. This merging reduces the total circuit area occupied by power supply components, isolation transformers, and associated circuitry.
Solution Approach 2:
The single isolated power supply is designed to universally drive multiple channels of solid-state relays. The isolator circuit distributes the isolated power supply output to multiple output switches, allowing one power supply to perform the function that previously required multiple separate power supplies.
3Device complexity
If a common ground is used in multi-channel solid-state relay circuits, then device complexity is reduced, but unintended activation occurs due to current flow through ground
Solution Approach 1:
The patent extracts the ground reference from the control circuit side and maintains it separate from the output circuit ground. The isolator circuit provides galvanic isolation that prevents ground current flow from affecting the control signals, thereby preventing unintended activation while maintaining a simple common ground configuration on each side.
Solution Approach 2:
The isolator circuit acts as an intermediary between the control circuit and the output circuits. It transfers control signals while maintaining galvanic isolation, preventing harmful ground current flow from propagating to the control side while still allowing simple ground configurations on both sides.
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
The solution reduces circuit area and cost while preventing unintended activation of solid-state relays, enhancing reliability and efficiency by using a single isolated power supply to drive multiple channels effectively.
Implementation Method 1
The diode is coupled to the first transistor, the second transistor, and ground, and is configured to block current flow from ground to the first transistor and the second transistor
Implementation Method 2
an isolator circuit coupled to the output switch and configured to activate the first transistor and the second transistor
Data Source
AI summary
A solid-state relay circuit includes an isolator circuit, a first output terminal, a second output terminal, and an output switch. The output switch is coupled to the isolator circuit, and includes a first transistor, a second transistor, and a diode. The first transistor is coupled to the first output terminal. The second transistor is coupled to the first transistor and the second output terminal. The diode is coupled to the first transistor, the second transistor, and ground, and is configured to block current flow from ground to the first transistor and the second transistor. The isolator circuit is coupled to the output switch and is configured to activate the first transistor and the second transistor.