Common-Source Transistor Pair With Kelvin Bypass Damping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In common-source or common-emitter configurations, the use of Kelvin connections can lead to undesirable resonant circuits due to parasitic inductance and gate capacitance, particularly in bidirectional switching applications, where a bypass current path is not designed for high and continuous currents, leading to oscillatory behavior and potential overload.
Innovation Solution
A common-source configuration with two transistors, where control resistors are relocated from the control terminals to the Kelvin source terminals, forming a secondary current path with significantly higher resistance, reducing the load current through the bypass path and maintaining the advantages of Kelvin connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control resistors are placed in the control terminal circuit, then the switching behavior can be adjusted, but the resistors are not located in the bypass path to prevent oscillatory behavior
Solution Approach 1:
The patent introduces an intermediary element (control resistor) placed specifically in the bypass path between the Kelvin source terminal and the power source terminal. This intermediary component serves as a damping element that prevents oscillatory behavior while maintaining the benefits of Kelvin connection for gate control decoupling.
Solution Approach 2:
The patent modifies the circuit configuration by changing the placement location of the control resistor from the control terminal circuit to the bypass path. This parameter change (location of the resistor) transforms the circuit behavior to eliminate oscillations while preserving switching performance adjustments.
2Reliability
If Kelvin source terminals are connected together in common-source configuration, then gate control is decoupled from load circuit, but a bypass current path is formed that is not designed for high and continuous currents
Solution Approach 1:
The patent converts the harmful bypass current path into a beneficial damping element by placing a control resistor in this path. The resistor, which would normally be seen as creating unnecessary current flow, is actually used to dampen oscillations and improve stability, thus converting a potential harm into a benefit.
Solution Approach 2:
The control resistor acts as an intermediary element in the bypass path, mediating between the Kelvin source terminal and power source terminal. It allows the bypass path to exist for gate control decoupling while preventing the harmful oscillatory behavior through its damping effect.
3Reliability
If control resistors are placed in the bypass path, then oscillatory behavior is prevented, but the bypass path resistance increases
Solution Approach 1:
The patent accepts the parameter change (increased bypass path resistance) as a necessary trade-off to achieve the primary goal of preventing oscillatory behavior. The control resistor value is carefully selected to provide sufficient damping while minimizing unnecessary energy loss in the bypass path.
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 configuration effectively reduces the load current through the bypass path, minimizing the risk of overload while retaining the benefits of Kelvin connections, suitable for AC and bidirectional DC applications, and can be implemented with various transistor types using a single-channel gate driver.
Implementation Method 1
At least one control resistor, which adjusts the switching behavior of the gate driver, is located in the secondary current path
Implementation Method 2
A standard gate driver circuit includes a gate driver that provides an output voltage or current
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a common-source configuration of two transistors (T1, T2), each with a source terminal (S1), a sink terminal (D1), and a control terminal (G1), comprising: - two control circuits (31, 32) for controlling each of the transistors (T1, T2) to control a load current through the common-source configuration, - a main current path (10) of the load current, and - a secondary current path (12) of the load current, which runs parallel to a section of the main current path (10), wherein one or more control resistors (R1, R2, R12) are arranged in at least one of the control circuits (31, 32), wherein the source terminals (S1, S2) are electrically connected, wherein the two sink terminals (D1, D2) and the two source terminals (S1, S2) are located in the main current path (10), running parallel to a section of the main current path (10) the side stream path (12) runs,one half of which is formed by a section of the first control circuit (31) and the other half by a section of the second control circuit (32), characterized in that at least one of said control resistors is arranged in the bypass path (12).