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Design >> Analog Design >> voltage conversion
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Message started by grosser on Jun 16^th, 2006, 7:00am

Title: voltage conversion
Post by grosser on Jun 16^th, 2006, 7:00am

hello

i need to convert 1.2V from bandgap to 1.22V for comparator input. How can i do that? The solution can't take to much current. (max 10uA)

any ideas?

regards

Title: Re: voltage conversion
Post by TOM_KOR on Jun 20^th, 2006, 8:04am

I thx , ouput stage bandgap add R(at upper BJT) or increse size of PMOS.
:-?

Title: Re: voltage conversion
Post by vivkr on Jun 21^st, 2006, 5:59am

grosser wrote on Jun 16^th, 2006, 7:00am:

hello

i need to convert 1.2V from bandgap to 1.22V for comparator input. How can i do that? The solution can't take to much current. (max 10uA)

any ideas?

regards

Hi,

Do you really need that 20 mV difference ? There are the following points to consider:

1. The variation of on-chip resistors in bandgaps gives approx. 50 mV variation in most cases across the process corners. Unless you are using a precisely trimmed bandgap, you may not gain much if you try to change the nominal value of your comparator reference to 1.22V.

2. Your comparator needs to have an offset appreciably lower than 20 mV.

May I ask why do you need such a precise comparator reference?

Regards
Vivek