High Voltage Comparator???

[eetrit]

I was wondering if anyone knows a company that produces a rail to rail comparator that can be supplied by at least 48V. I would rather not use an op-amp because they are very very slow compared to a good comparator and the comparator has the open collector output that i need to decrease the components in my circuit. Thanks for any help.

 

[nbucska]

What are the specs you need ?

<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032

 

[eetrit]

I'm trying to make a basic switching power supply with a 48V supply rail-to-rail output comparator. An open collector output would be perfect.

 

[IRstuff]

What wrong with using resistor dividers?

TTFN

 

[Warpspeed]

Agree with IRstuff, resistive dividers on the inputs, and use the comparator output to drive a small MOSFET with open drain. That just about removes any real practical voltage constraints on either input or output. With a bit of detailed design it could be made quite fast.

 

[eetrit]

I am currently using a resitor devider-esque circuit with a FET. We would really like to use a nice comparator to decrease board real estate and increase response time. Comparators are in ns where the current system takes a couple us to become nice and stable. Just a thought though. These comparators would really help out for the next project. I really need a comparator though, NOT and op-amp. Thanks.

 

[IRstuff]

So why not use a comparator with a resistor divider?

Or, use high speed op-amps. The typical switching power supply is only running in the sub-MHz range.

If you're that desperate for board space, then maybe you need to look at getting a custom hybrid.

TTFN

 

[rob8748]

Review what they have, I've used the parts, while not low cost, they can get you buy if you are not planning to design in and use.
Rob.

http://eportal.apexmicrotech.com/mainsite/index.asp