Surge Voltage Suppression Circuit Using Current Amplification
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Solution Overview
Problem
Existing surge voltage control circuits face challenges in effectively suppressing surge voltages due to transistor switching, as the displacement current from capacitors is partially absorbed by gate drivers, leading to reduced effectiveness and potential oscillation issues with high-capacity capacitors.
Innovation Solution
The proposed electronic circuitry includes a surge voltage detection circuit that generates a first signal indicating a current, which is then amplified by a current generation circuit to produce a second current larger than the first, effectively suppressing surge voltages without the need for high-capacity capacitors, thereby reducing costs and preventing oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacity of the capacitor is increased to increase the displacement current supplied to the transistor, then the surge voltage suppression effect is improved, but oscillation of the transistor may occur due to the effect of parasitic inductance
Solution Approach 1:
The patent introduces a current amplifier as an intermediary component between the capacitor and the transistor gate. The current amplifier receives the displacement current from the capacitor and amplifies it before supplying to the transistor gate. This mediator allows the system to achieve sufficient gate current for surge suppression without requiring a large capacitor capacity, thereby avoiding the parasitic inductance oscillation problem that would occur with high-capacity capacitors.
2Reliability
If the capacity of the capacitor is increased to increase the displacement current supplied to the transistor, then the surge voltage suppression effect is improved, but the cost increases due to requiring a capacitor with high withstand voltage
Solution Approach 1:
The current amplifier serves as a mediator that enables the system to achieve the desired displacement current effect without using a high-capacity, high-withstand-voltage capacitor. By amplifying the current from a smaller capacitor, the system avoids the high cost associated with high-capacity capacitors while maintaining effective surge voltage suppression.
Solution Approach 2:
The patent changes the current parameter through the current amplifier, which amplifies the displacement current from the capacitor by a specific gain factor. This parameter transformation allows the use of a smaller capacitor with lower withstand voltage requirements, thereby reducing cost while maintaining the necessary current level for effective surge suppression.
3Reliability
If a capacitor is arranged to generate displacement current to suppress surge voltage, then the surge voltage suppression is achieved, but the displacement current is partially absorbed by the gate driver, decreasing the current input to the control terminal
Solution Approach 1:
The current amplifier acts as an intermediary that compensates for the current loss in the gate driver. It receives the displacement current from the capacitor and amplifies it to a level that ensures sufficient current reaches the transistor control terminal despite the gate driver's current absorption, thereby maintaining effective surge voltage suppression.
Solution Approach 2:
The current amplifier provides preliminary amplification of the displacement current before it enters the gate driver stage. This preliminary action ensures that even after the gate driver absorbs some current, the remaining current supplied to the control terminal is still sufficient for effective surge suppression, counteracting the expected current loss.
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 effectively suppresses surge voltages while reducing the cost and parasitic inductance effects, ensuring reliable transistor operation without the need for large capacitors, and allows for efficient response to fast phenomena like surge voltages.
Implementation Method 1
a capacitor is arranged to be electrically coupled at a portion where the surge voltage is generated and a displacement current of the capacitor is input to a control terminal of the transistor
Implementation Method 2
a current amplifier configured to amplify a current in response to input of the first signal and generate a second current that is larger than the first current
Data Source
AI summary
According to one embodiment, electronic circuitry includes a first surge voltage detection circuit configured to detect a surge voltage generated due to switching of a switching device and generate a first signal indicating a first current; and a current generation circuit configured to generate a second current larger than the first current by amplifying a current in response to input of the first signal and output the second current to a control terminal of the switching device.