Mastering MOSFET High-Frequency Switching
When building power converters, LED drivers, or motor controllers, high-frequency switching with MOSFETs is essential. But many hobbyists face excess heat or efficiency loss when switching above 50kHz. The problem? Improper MOSFET selection or gate drive setup.
🔧 The Problem :
At high frequencies, gate charge (Qg) becomes critical. If you use a standard MOSFET without considering its Qg or gate drive current, switching losses dominate and cause heating or reduced efficiency.
💡 The Solution :
Pick a low Qg MOSFET with fast switching characteristics, and pair it with a suitable gate driver IC that can source and sink enough current quickly—ideally >1A for frequencies above 100kHz.
🧪 Practical Example :
If you’re building a 100kHz boost converter for an LED strip, and your MOSFET has a Qg of 40nC, to switch efficiently:
Required gate current (I) = Qg × f = 40nC × 100kHz = 4mA
But add margins: use a gate driver capable of at least 100mA to 500mA.
🔌 Sample Products :
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