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Voltage conversion 3.3v -> 24v

Altera_Forum
Honored Contributor II
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Hello all, 

 

I have a DE-2 board and I am looking to control a few PLCs. I need to take the 3.3v and convert it to 24v, as well as, take 24v and convert it to 3.3v. The DE-2 Board is acting like a divide by circuit. It takes an encoder signal at 24v (max 100kHz) as the clock and divides it down to produce a trigger. The divisible number is supplied via the 24v to 3.3v as a 16 bit value. (4 bits sent at a time)  

 

Going from 24v to 3.3v I believe I can just do a divide by circuit for the encoder but the 3.3v to 24v seems to be tricky at speeds greater than 5kHz. 

 

I have found so far: 

 

3.3v->5v 74HCT244 

 

5v->24v ? 

 

Thanks
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Altera_Forum
Honored Contributor II
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These work nicely for switching higher voltages from FPGA IOs: 

 

http://www.irf.com/product-info/datasheets/data/pvg612.pdf 

 

but they're a little slow for your needs. 

 

Have you though of using a power supply MOSFET driver? 

 

For example, look at page 25 of this schematic: 

 

http://www.ovro.caltech.edu/~dwh/carma_board/gda06rb004_carma_v0.87_dec03.pdf 

 

The Texas Instruments UCC27223 are logic-level input MOSFET drivers. You could use that component, or something similar, to switch 24V pretty rapidly, you'd just need to use MOSFETs with the right voltage rating. 

 

Cheers, 

Dave
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Altera_Forum
Honored Contributor II
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Most gate driver IC (also UCC27223) are limited to 18 or 20 V supply voltage. For lower current and higher output voltage, you can either use special interface drivers, or e.g. fast operational amplifiers/comparators.

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