Semiconductor Gate Driver Circuit for EMI Reduction
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Solution Overview
Problem
High-speed semiconductor switching devices face challenges with Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) issues due to fast rise and fall of high voltages and currents, which interact with parasitic elements in circuits, necessitating improved driver circuits.
Innovation Solution
A driver circuit for high-speed semiconductor switching devices that includes a voltage regulator to generate a first drive voltage from a supply voltage, a drive controller to provide a difference between the supply and first drive voltages as a second drive voltage, and a storage element to store the second drive voltage, allowing for efficient switching with reduced EMI and EMC by providing a positive voltage to turn on and a reverse polarity voltage to turn off the semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If fast switching of semiconductor devices is implemented, then switching speed is improved, but Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) issues worsen
Solution Approach 1:
The patent applies preliminary anti-action by pre-charging a capacitor to a voltage higher than the supply voltage before the semiconductor device switches off. This pre-prepared high voltage is immediately applied to the gate when switching is required, actively counteracting the slow turn-off effect of the body diode and preventing the generation of EMI and EMC issues before they can occur during the switching transition.
Solution Approach 2:
The patent implements preliminary action by using a dedicated charging circuit to charge a capacitor to a voltage level exceeding the supply voltage during the on-state of the semiconductor device. This preparatory charging action ensures that the necessary high voltage is available immediately when needed for fast turn-off, eliminating the need to charge the capacitor during the critical switching transition period.
2Device complexity
If conventional driver circuits are used with single supply voltage, then device complexity is reduced, but switching performance deteriorates due to inability to provide reverse polarity voltage
Solution Approach 1:
The patent introduces a capacitor as an intermediary energy storage element between the single supply voltage source and the gate drive circuit. This capacitor acts as a mediator that can deliver both positive voltage (during on-state) and negative voltage relative to source (during off-state) to the gate, enabling full bidirectional control while maintaining a simple single-supply architecture.
Solution Approach 2:
The patent changes the voltage parameter dynamically by charging the capacitor to exceed the supply voltage during on-state, then allowing it to discharge below the supply voltage during off-state. This parameter change approach enables the generation of both positive and negative gate drive voltages from a single positive supply, achieving dual-polarity drive functionality without complex voltage generation circuits.
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 driver circuit enables fast switching of large voltages or currents while minimizing EMI and EMC issues, effectively addressing the challenges posed by high-speed semiconductor devices by generating necessary drive voltages from a single supply potential.
Implementation Method 1
a voltage regulator to generate a first drive voltage from a supply voltage
Implementation Method 2
a storage element to store the second drive voltage
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A driver for a semiconductor switching device can be configured to step down a supply voltage to generate a first drive voltage. The driver can also generate a second drive voltage equal to the potential difference between the supply voltage and the first drive voltage. The driver can supply the first drive voltage to a control gate of the semiconductor switching device during a first state of a control signal, and a reverse polarity of the second drive voltage during a second state of the control signal