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🛠️ 【硬體】設計細節 🛠️

反相電壓保護(二極體)

有些晶片正負極接返會有不可逆的損害。

二極體是最簡單保護電源反接的方式。

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圖中 VR1 是 XT-30 端子的電源供應口。
當電源反接時,蕭特基二極體 SS54B 會阻斷逆向壓差電流。


二極體選擇

  • 電源保護建議使用蕭特基二極體(Schottky diode, SBD),反應速度最快。

  • 須注意的參數,以 SS520B 為例:

    • 逆向偏壓 Peak Reverse Voltage (Vr)
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    • 順向壓降 Forward Voltage Drop (Vf)
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  • 結論:SS520B 能防反接 200V;但代價是正常工作時,源電壓會被降低 1V