Protection device and control circuit for a semi-conductor switch and method for controlling a semi-conductor switch
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Solution Overview
Problem
As semiconductor switches operate at higher speeds, existing surge protection devices face challenges in reliably detecting overvoltages due to their capacitive properties, which can affect response voltage and behavior, potentially leading to damage or premature aging.
Innovation Solution
A protective device for semiconductor switches that includes a capacitive component, an integrator, and a comparison device to determine and manage the charge in the capacitive component, allowing for early detection and countermeasures against overvoltages, such as controlling the switch to reduce voltage, by integrating the charging current and comparing it against a predetermined limit value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional avalanche diodes are used for overvoltage detection, then overvoltage protection is provided, but the capacitive properties of the diodes negatively impact response voltage and behavior at high switching speeds
Solution Approach 1:
The patent extracts the capacitive component from the conventional avalanche diode structure and treats it as a separate, identifiable element. By integrating this capacitive component into the protection circuit design, the system can account for its charging behavior and use it as a trigger mechanism, thereby eliminating the negative impact of capacitance on response voltage while maintaining high-speed switching capability
Solution Approach 2:
The patent changes the detection parameter from voltage-based (conventional avalanche diode breakdown voltage) to charge-based (capacitive component charge quantity). This parameter transformation allows the system to detect overvoltages by monitoring the charging state of the capacitive component, which provides a more accurate and timely response at high switching speeds without being affected by the diode's capacitive properties
2Productivity
If switching speeds increase, then productivity is improved, but the capacitive properties of protective components cause delayed or inaccurate overvoltage detection
Solution Approach 1:
The patent implements preliminary action by using the integrator to continuously monitor and integrate the charging current of the capacitive component before an overvoltage event occurs. This allows the system to detect the onset of overvoltage conditions earlier and more accurately, triggering protective measures before the capacitive component becomes overloaded, thereby maintaining measurement precision at high switching speeds
Solution Approach 2:
The patent establishes a feedback mechanism where the charge quantity of the capacitive component is continuously measured by the integrator and comparator, and this information is fed back to control the semiconductor switch. This closed-loop feedback ensures accurate overvoltage detection and timely protective action, preventing the capacitive properties from causing detection delays or inaccuracies
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
Enables reliable and rapid detection of overvoltages at high switching speeds, preventing damage by initiating countermeasures before capacitive components are overloaded, ensuring effective overvoltage protection for both slow and fast switching processes.
Implementation Method 1
a capacitive component (11), an integrator (12) and a comparison device (13). The integrator (12) is designed to integrate a charging current into the capacitive component (11)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a protection for a semi-conductor switch against over voltages. A capacitive element is provided on an inlet connection of the semi-conductor switch. The load amount, which flows into said capacitive element, is integrated in order to trigger a protection function when a thersehold value is exceeded.