带隙基准输出电压的问题

sean_4413 · 发表于 2009-3-8 16:16:46

原帖由 prof3 于 2009-3-8 16:06 发表

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Step 1.  Pls check OPA gain at low temperature first see if still have enough Gain.
Step 2.  Pls check your startup circuit at low temperature see if correctly startup

If both above if OK.  Go to ...

thank you!好的，我试试

sean_4413 · 发表于 2009-3-9 19:33:02

问题好像解决了，因为之前做仿真时，我仅仅仿真的是带隙基准，运放工作的电流源我是用一个固定电压代替，而没有带入电流源电路一起仿真。

但现在又有新问题，那就是在-45到125摄氏度之间，电压随温度升高而升高，从-45摄氏度的1.32V一直增加到125摄氏度的1.42v，我将R2和R3阻值变小，问题仍然没有解决。还请大虾们赐教！！

prof3 · 发表于 2009-3-10 02:30:50

That is due to your temp coef. (PTAT and Delta(Vbe) is not cancelled well. Now the case is your temp is positive, so recommend change the R (in Delta(Vbe)/R) to increase the negative temp coef. so that you will get zero temp. at room temp.

sean_4413 · 发表于 2009-3-10 22:17:09

原帖由 prof3 于 2009-3-10 02:30 发表

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That is due to your temp coef. (PTAT and Delta(Vbe) is not cancelled well. Now the case is your temp is positive, so recommend change the R (in Delta(Vbe)/R) to increase the negative temp coef. so tha ...

谢谢，问题已经解决了！