Integrated Submodule for Power Semiconductor Voltage Clamping
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Solution Overview
Problem
Existing power semiconductor modules face issues with parasitic inductances and ohmic resistance in external clamping circuits, leading to ineffective voltage clamping during fast switching processes, which can result in transistor destruction due to excessive short-circuit currents.
Innovation Solution
A submodule with a monolithically integrated semiconductor structure that includes a series resistor and a dual diode structure, placed directly adjacent to the power semiconductor switch, reduces parasitic inductances and ohmic resistance by integrating the clamping diodes close to the transistor, effectively limiting gate voltage and preventing overvoltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete clamping diodes are mounted on external printed circuit boards, then the clamping circuit can be implemented, but parasitic inductances and ohmic resistance increase leading to ineffective voltage clamping
Solution Approach 1:
The patent combines the clamping diodes with the power semiconductor switch into a single integrated structure. The semiconductor chip contains both the power switch and clamping diodes monolithically integrated, eliminating the need for separate discrete components and external circuit boards. This merging reduces parasitic inductances and ohmic resistance while maintaining effective voltage clamping functionality.
Solution Approach 2:
The patent introduces an intermediate integrated structure that serves as a bridge between the power semiconductor switch and the clamping circuit. This intermediate semiconductor chip with integrated clamping diodes acts as a mediator, providing low-parasitic connection paths while implementing the clamping function directly at the switch location.
2Ease of manufacture
If clamping diodes are placed far from the power semiconductor, then manufacturing is simplified, but voltage drops accumulate making the clamping ineffective
Solution Approach 1:
The patent merges the clamping diodes and power semiconductor switch into a single monolithically integrated semiconductor chip. This eliminates the trade-off between manufacturing simplicity and clamping accuracy by making the components so close that manufacturing remains practical while electrical performance is optimized.
3Reliability
If gate series resistors are used to limit charging current, then voltage rise is regulated, but parasitic voltages add up during fast switching reducing clamping effectiveness
Solution Approach 1:
The patent combines the gate series resistor and clamping diodes into a single integrated semiconductor structure. This merging minimizes the loop area and parasitic inductances associated with the resistor-diode connection, reducing parasitic voltages during fast switching while maintaining gate voltage control functionality.
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 integrated submodule enhances the effectiveness of the clamping circuit, reducing the risk of transistor destruction by directly limiting gate voltages and maintaining the transistor within a safe operating area during short-circuit events.
Implementation Method 1
When the breakdown voltage of the double diode is reached (e.g. 16V), the double diode current path becomes low-impedance. A further charging current then no longer leads to an increase in the voltage present at the gate of the circuit breaker, but the value is fixed at e.g. 16V.
Implementation Method 2
The gate series resistor also forms an RC element with the gate capacitance, e.g. of an IGBT or MOS transistor. The gate series resistor is used to regulate the voltage rise of the RC element.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A submodule (22b) for a power semiconductor module (2) includes - at least a part of a carrier (6), - a conductor track (24) arranged on the part of the carrier (6), - a monolithically integrated semiconductor structure (26) applied to the conductor track (24), which includes - a contact surface (50) connecting the semiconductor structure (26) to the conductor track (24), - a first (28a) and second terminal (28b) and an integrated ohmic resistor (40) connected between these terminals (28a,b), and - a third terminal (28c) and an integrated double diode structure (38) connected between these (28c) and the second terminal (28b).A power semiconductor module (2) comprises - a first submodule (22b) as above, and - a power semiconductor (8) having a control input (21) arranged on the carrier (6) and forming a second submodule (22a) with it, wherein - the first submodule (22b) is placed in close proximity to the power semiconductor (8) on the carrier (6), and - the control input (21) is connected to the second terminal (28b) of the first submodule (22b).