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A voltage regulator is a device which takes an input voltage and outputs a stable fixed voltage
1.齊納二極體 (Zener Diode)
- 1.12V-->5V (Select a proper Zener Diode voltage)
- 2.最小輸入電壓須比輸出的穏壓大2V以上
- 1.LM7805 ==> 5V; LM7812==> 12V
- 2.最小輸入電壓須比輸出的穏壓大2V以上
- max allowed IN/OUT voltage difference which is 40v
- OUT = 1.25*(1+R2/R1)
4.參考電壓IC : LM385 , AD580
那如何做5V--> 3.3V ? or 3.3v --> 1.8v
- 使用線性穩壓器 LDO (Low Dropout) , 只需要差到0.5V以上
- LM2940, LM2941
- LM317
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