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PSoC 5, 3 & 1 MCU

Anonymous
Not applicable

Dear All,

   

I am trying to implement a PI controller for a power converter. Attached is the schematic diagram of the analog part that I want to implement on PSoC-5LP.
The problem is that PI's opamp output is -ve and opamps in PSoC do not support  a -ve voltage. 
Any help in this regard would be appreciated.

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8 Replies
Honored Contributor II
        You can't use a negative voltage on PsoC parts . You will need an external Opamp.   
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Valued Contributor II
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Anonymous
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Thanks for your reply.
But the problem remained intact as I am using PI controller whose output is -ve and input is +ve (in simulation results in PSIM).

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Valued Contributor II

It is not difficult to create using a converter TIA or OPAMP

   

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Anonymous
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Thanks for your reply!

But, TIA also couldn't solve the problem. If you see the attached pic (with my first post), there is -ve signal in between two opamps. So, the problem is that when I feed a +ve signal to the opamp1 the output will be -ve and will go to the input of the opamp2.  With power supply range of 0 to +ve of opamp1 (i.e., opamps in psoc), at output I only get 0 instead of the -ve output.

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Esteemed Contributor II

When you set Vref to +ve/2 all will be good.

   

 

   

Bob

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Anonymous
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In fact, the range of Vref is relative to the +ve input (from a current sensor) to opamp1. So, if I will keep Vref/2 (0.5) eventually input to opamp1 will also be 0.5 because, Its a PI controller loop. Long story short, the output of opamp1 will remain -ve. 

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Anonymous
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Problem solved using external opamps IC with dual power supply.  

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