Switched Inductive Gate Drive for Parasitic Turn-On Suppression
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Solution Overview
Problem
Existing power conversion systems face reliability issues due to switching induced transients that can cause unintended turn-on or damage to circuit components, particularly in high-voltage applications, and existing solutions like split supplies are not practical for consumer or low-power applications.
Innovation Solution
The implementation of a switched inductive storage element, such as an inductor, which is energized between a supply node and a gate node of the gated device, allowing the gate to be driven below the local ground potential to mitigate parasitic turn-on during switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If split supplies are used to mitigate parasitic turn-on, then device reliability is improved, but device complexity and power requirements increase making it impractical for consumer applications
Solution Approach 1:
An inductor is introduced as an intermediary component between the gate driver and the switching device. The inductor stores energy during the on-state and releases it during turn-off to generate a negative voltage spike that actively pulls the gate voltage below threshold, preventing parasitic turn-on without requiring complex split power supplies
Solution Approach 2:
The invention changes the voltage parameter at the gate by using the inductor to generate a transient negative voltage spike during turn-off. This dynamic voltage parameter change actively suppresses parasitic turn-on by ensuring the gate voltage remains below the threshold voltage during critical switching transitions
2Object-affected harmful factors
If inductive storage element is switched to drive gate below ground potential, then switching induced noise is reduced, but circuit complexity increases
Solution Approach 1:
The inductor serves as a mediator that couples the power rail to the gate driver circuit. By switching the inductor on and off at appropriate times, it generates controlled negative voltage spikes that suppress switching noise and prevent parasitic turn-on, adding minimal complexity while effectively addressing the harmful electromagnetic transients
Solution Approach 2:
The inductor is switched periodically in synchronization with the switching device operation. During the on-state, the inductor charges; during turn-off, it discharges to generate the negative voltage spike. This periodic switching action aligns with the operating cycle to continuously suppress switching induced noise without requiring additional control complexity
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 reduces switching induced noise, preventing unintended device turn-on and potential damage, while being practical for consumer and low-power applications without requiring additional voltage sources.
Implementation Method 1
an inductive storage element, which is energized between a supply node and a gate node
Implementation Method 2
allowing the gate to be driven below the local ground potential to mitigate parasitic turn-on during switching
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A switched inductive storage element to enhance gate drive at turn-off is described herein. An inductive storage element (e.g., an inductor) may be switched between a supply node and a gate node of a gated device (e.g., a low-side device and/or a high-side device). While coupled to the supply node, the inductive storage element may be energized; and subsequently, while coupled to the gate node of the gated device, the inductive storage element may drive the gate node (i.e., the gate of the low-side and/or high-side device) below the local ground potential.