Semiconductor Drive Circuit Parasitic Oscillation Suppression
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Solution Overview
Problem
High power semiconductor devices with multiple switching elements connected in parallel often experience severe parasitic oscillations due to parasitic capacitance and stray inductance, requiring numerous diodes for suppression, which complicates the device configuration.
Innovation Solution
A semiconductor device with a drive circuit that includes inserted circuits with diodes connected in parallel to each semiconductor element, interrupting current flow unless a positive voltage exceeds the sum of the forward voltages of the diodes, effectively suppressing parasitic oscillations with a simpler configuration by reducing the number of required diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If balance resistor units with diodes are connected to each semiconductor switching element to suppress parasitic oscillations, then parasitic oscillations are suppressed, but the device configuration becomes complicated due to the large number of diodes required
Solution Approach 1:
The patent merges multiple diode functions into a single inserted circuit unit that can be shared among multiple semiconductor elements. Instead of connecting individual diodes to each switching element, one inserted circuit with two anti-parallel diodes serves multiple elements, reducing component count while maintaining oscillation suppression effectiveness
Solution Approach 2:
The inserted circuit is designed as a universal component that can suppress parasitic oscillations for multiple semiconductor switching elements simultaneously. The circuit with anti-parallel diodes provides bidirectional protection and can be shared across different switching elements, making a single circuit perform the function of multiple individual diodes
2Reliability
If many diodes are connected to each semiconductor switching element to suppress parasitic oscillations, then oscillation suppression is effective, but the number of components increases significantly
Solution Approach 1:
Multiple diode functions are merged into a single inserted circuit unit. The circuit contains two diodes connected in anti-parallel configuration, and this single unit can serve multiple semiconductor switching elements, dramatically reducing the total number of diodes required in the system
Solution Approach 2:
Instead of replicating individual diodes for each switching element, the patent uses a standardized inserted circuit unit that can be copied and connected to multiple elements. This modular approach reduces component variety and simplifies the overall configuration while maintaining the necessary protection 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
The solution effectively suppresses parasitic oscillations of small and large amplitudes, simplifying the device configuration and reducing the number of inserted circuits needed, while maintaining low voltage across semiconductor elements.
Implementation Method 1
a current flowing from the first semiconductor elements to the second semiconductor elements is interrupted unless the positive voltage exceeds the sum of a forward voltage of the first diode of the first inserted circuit and a forward voltage of the second diode of the second inserted circuit
Data Source
AI summary
A plurality of semiconductor elements connected in parallel with one another include a plurality of first semiconductor elements and a plurality of second semiconductor elements. A drive circuit to provide a gate signal to each of the plurality of semiconductor elements EL includes a main circuit and a plurality of inserted circuits including a first inserted circuit and a second inserted circuit. The first inserted circuit is inserted between the main circuit and the plurality of first semiconductor dements. The second inserted circuit is inserted between the main circuit and the plurality of second semiconductor elements. Each of the first inserted circuit and the second inserted circuit includes a first diode having a forward direction toward the main circuit and a second diode connected in anti-parallel with the first diode.