Drive Circuit Dynamic Mode Switching for EMI Reduction
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Solution Overview
Problem
Existing gate drive control technologies face challenges in minimizing Electro-Magnetic Interference (EMI) noise while maintaining a compact circuit size, as the on-resistance drive mode generates significant EMI noise but requires large drive currents, and the constant current drive mode reduces EMI noise but necessitates a large device size.
Innovation Solution
A drive circuit that incorporates a current mirror circuit and a potential change circuit, allowing switching between constant current drive and on-resistance drive modes, utilizing a configuration with P-channel and N-channel MOSFETs to manage control potentials and reduce circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If constant current drive mode is used, then EMI noise is reduced, but device size becomes large
Solution Approach 1:
The patent implements dynamic switching between constant current drive mode and on-resistance drive mode based on operational requirements. The control circuit dynamically adjusts the drive mode: using constant current mode during switching transitions to minimize EMI noise, and on-resistance mode during steady-state operation to reduce device size requirements.
Solution Approach 2:
The patent changes the drive mode parameter dynamically by adjusting control potentials. The control circuit modifies the gate drive characteristics by switching between two distinct drive modes, thereby adapting the device behavior to different operational phases without requiring a large device size throughout.
2Power
If on-resistance drive mode is used, then drive current is large, but EMI noise increases
Solution Approach 1:
The control circuit dynamically selects drive modes based on operational phase. During switching transitions where high drive current is needed for fast switching, on-resistance mode is used. During steady-state operation where lower current suffices, constant current mode is activated to minimize EMI noise while maintaining adequate drive current.
Solution Approach 2:
The patent applies periodic switching between drive modes corresponding to different phases of device operation. The control circuit alternates between on-resistance drive mode during switching events and constant current drive mode during steady-state periods, creating a rhythmic pattern of mode transitions that balances performance and noise reduction.
3Object-affected harmful factors
If both constant current drive and on-resistance drive modes are used, then EMI noise is reduced and circuit area is minimized
Solution Approach 1:
The patent implements a universal drive circuit that can operate in both constant current drive mode and on-resistance drive mode using the same hardware infrastructure. The control circuit provides multi-functionality by selecting between two drive modes without requiring separate dedicated circuits for each mode, thereby minimizing overall circuit area while achieving EMI noise reduction.
Solution Approach 2:
The control circuit acts as an intermediary that manages the switching between constant current drive mode and on-resistance drive mode. This intermediary component coordinates the operation of both drive modes, enabling the system to achieve EMI noise reduction and compact size without requiring complex independent circuits for each mode.
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
Enables efficient switching between drive modes with reduced EMI noise and compact circuit design, effectively addressing the size and noise issues of previous technologies.
Implementation Method 1
The reference transistor, which is connected to the output transistor in a current mirror manner, supplies a mirror current to the output transistor.
Implementation Method 2
The potential change circuit connected to the reference transistor changes a control potential of the output transistor from a potential during mirror operation of the current mirror circuit.
Data Source
AI summary
A drive circuit of the present invention, which drives a switching device in response to a control signal, includes: a current mirror circuit including an output transistor connected to a control electrode of the switching device and a reference transistor that is connected to the output transistor in a current mirror manner and supplies a mirror current to the output transistor; and a potential change circuit that is connected to the reference transistor and changes a control potential of the output transistor from a potential during mirror operation of the current mirror circuit.