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how to find bias so that OP amp output range is max?

only6512

Feb 15, 2014
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hello,everyone , i have a question about (d) i just know that maxium output may be V_Bp2+|Vov7| mininum:V_BN2-v_ov9 can anyone help me? thanks ^^

*by the way ,i want to check the answer to (c) my answer:max:5-|V_ov4|+V_t1;min:-5+|V_ov3|+|V_ov1|+V_t1 are my answers right? thans again^^
 

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Arouse1973

Adam
Dec 18, 2013
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Can you explain What V_0V4 and V_t1 is. I would have thought for the max you should be taking away all relevant voltage and not adding them as in -V_t1 and not +V_t1? What are these voltages?
Adam
 

Arouse1973

Adam
Dec 18, 2013
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Ah just figured your Vt1 is what is called VTN and is the threshold voltage. I am not sure but I think it should be this
Max = VDD-VSD4+VTN and Min = VSS+VSD3+VGS1
 

only6512

Feb 15, 2014
18
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Feb 15, 2014
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thanks for your reply!
V_ov4 is the overdrive voltage of mosfet 4
V_t1 is the threshold voltage of mosfet 1
and your answer:
Max = VDD-VSD4+VTN and Min = VSS+VSD3+VGS1
I think it is the same as mine:
5-|V_ov4|+V_t1;min:-5+|V_ov3|+|V_ov1|+V_t1
 

Arouse1973

Adam
Dec 18, 2013
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Yep Correct. I think the other question is asking you what bias voltages you need on the gates of the depletion Mosfets to give half supply point on the output, and in this case I think the output should be 0V. The other guys might read this differently. I think they mean symmetry and not actually maximum or minimum voltage.
Adam
 
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