Overvoltage Protection Circuit with Bidirectional Switch
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Solution Overview
Problem
Existing overvoltage protection devices often fail to adequately protect sensitive electronic equipment from transient overvoltages and surge currents, as the residual voltage or current from Surge Protective Devices (SPDs) can exceed the immunity level of the equipment, leading to damage.
Innovation Solution
A circuit protection device with an overvoltage monitor circuit and bi-directional switch that detects overvoltage conditions and limits current flow, combined with a bi-directional voltage limiter to restrict voltage to a predefined safe level, ensuring the equipment is not damaged by excessive voltage or current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional Surge Protective Device (SPD) is used to protect against transient overvoltages and surge currents, then the equipment is protected from severe surges, but the residual voltage or current from the SPD may still exceed the immunity level of sensitive electronic equipment and cause damage
Solution Approach 1:
The patent introduces an overvoltage protection device as an intermediary component between the SPD and the sensitive electronic equipment. This intermediary device includes a monitor circuit that detects overvoltage conditions and controls a bidirectional switch to interrupt current flow, and a bidirectional voltage limiter that clamps voltage to a safe level. This mediator protects the equipment from the harmful residual effects of the SPD during surge events.
Solution Approach 2:
The overvoltage protection device monitors its own operating conditions through the monitor circuit, which detects overvoltage conditions on the power supply circuit. The device automatically activates the bidirectional switch and voltage limiter when overvoltage is detected, and self-resets when conditions return to normal, providing automatic self-service protection without external intervention.
2Reliability
If the immunity level of sensitive electronic equipment is very low, then the equipment is more vulnerable to damage, but standard SPD protection is insufficient to reduce residual voltage and current below the equipment's immunity threshold
Solution Approach 1:
The patent changes the voltage parameter by using a bidirectional voltage limiter that actively clamps the voltage to a predefined safe level that is below the equipment's immunity threshold. The monitor circuit continuously monitors voltage parameters and activates protection when thresholds are exceeded, dynamically adjusting the protection level to match the specific immunity requirements of low-immunity equipment.
Solution Approach 2:
The protection function is segmented into distinct components: a monitor circuit for detection, a bidirectional switch for current interruption, and a bidirectional voltage limiter for voltage clamping. This segmentation allows each component to specialize in a specific aspect of protection, enabling precise control over residual voltage and current to meet the stringent requirements of low-immunity equipment.
3Object-affected harmful factors
If a bidirectional switch and voltage limiter are added to provide enhanced protection, then residual voltage and surge current are reduced to safe levels, but the device complexity increases
Solution Approach 1:
The bidirectional switch and bidirectional voltage limiter serve multiple functions: they protect against both positive and negative overvoltage conditions, provide current interruption, and clamp voltage to safe levels. The monitor circuit also provides multiple functions by detecting both overvoltage conditions and controlling the activation of protection mechanisms. This multi-functionality reduces the need for separate components for each protection function.
Solution Approach 2:
The patent combines the monitoring function, switching function, and voltage limiting function into a single integrated overvoltage protection device. The monitor circuit, bidirectional switch, and bidirectional voltage limiter are combined in one unit with coordinated operation, reducing the overall system complexity compared to having separate independent protection devices for each function.
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
Effectively reduces the residual voltage and surge current to within acceptable operational ranges, preventing damage to sensitive equipment during transient events like lightning strikes, thereby enhancing protection and reducing downtime.
Implementation Method 1
a bi-directional voltage limiter responsive to the change in the state of the overvoltage output and a bi-directional voltage limiter connected across output terminals of the circuit protection device may be operable to limit an overvoltage to a predefined voltage limit
Implementation Method 2
an overvoltage monitor circuit that is operable to monitor a power supply circuit to detect an overvoltage condition on the power supply circuit
Implementation Method 3
A bi-directional switch may be operable to interrupt or limit current flow though the power supply circuit to the equipment
Data Source
AI summary
A circuit protection device includes an overvoltage monitor circuit that is operable to monitor a power supply circuit to detect an overvoltage condition on the power supply circuit and to change a state of an overvoltage output responsive to the overvoltage condition on the power supply circuit. A bi-directional switch is operable to interrupt or limit current flow though the power supply circuit responsive to the change in the state of the overvoltage output. A bi-directional voltage limiter is connected across output terminals of the circuit protection device and is operable to limit an overvoltage to a predefined voltage limit.