Help me increase the PSR of a BGR

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i looked related topics but i cannot increase the psr of my BGR. what can i do about it, pls help...
thanks from now
 

HELP: OPAMP output voltage

U have to check the work region of the transistors, specially the current mirrors, of your leg that give currents to the resistor and the bipolar transistor. Somehow there must have been in linear region when vdd is higher. You can try reduce the gain of your opamp and decrease the size of the current mirrors.

thanks
arsenal
 

Re: HELP: BGR PSR

thanx arsenal...
then, what can i do about psr of BGR do you have any idea??? help me please
its ok @ 3.3V but @1V... catastrophe!!!
heeeeeelp...

Added after 4 hours 25 minutes:

can we calculate psr with the data:
supply voltage=1V and reference (output) voltage=0.5V

can you give me a formula and an answer???
 

Re: HELP: BGR PSR

try to decrease the PSR of the OPAMP, this will yield to an increase in the PSR of the bandgap reference
 

Re: HELP: BGR PSR

thanx for your answer but i do not have any idea about how can i decrease the psr of an opamp cause i never worked on psr before??? moreover, it is hard to say that i could understand the psr concept completely.

i am waiting for your answer
 

HELP: BGR PSR

What is psr? Power supply rejection?
Some reference say the PSR almost equal the open
loop gain.
 

Re: HELP: BGR PSR

yes, it is power supply rejection and i cannot find a good definition about it.
i am looking for someone who can define psr to me???
 

Re: HELP: BGR PSR

power supply rejection means the gain seen by a signal injected from the supply node, you need to measure this in order to have a figure of the circuit immunity to supply noise (noise on supply rails due to digital activity on other paths which are coupled to the vdd rail)

u need to analyze the circuit and to find the poles and zeros which control the transfer function from the vdd to the output, and by controlling the positions of these poles/zeros you can achieve the psr u want
 

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    universeee

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Re: HELP: BGR PSR

thank you eng_Semi, now i can get the concept at last

i will try to increase the psr as you told. i hope it works with my design.
 

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