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optocouple suggestion?

qwertyqwq

Member
salut a tout !

I'm looking for a optocoupler ,which can turn on and turn of about 30kHz . There will be a mosfet at its output. Opto's supply voltage will around 12-24V. Also switching signal is from opamp's output, so signal current will be low. Any suggestion please ???
 

unclejed613

Well-Known Member
Most Helpful Member
yes, switching time is 0.5uS which would be usable up to about 500khz
 

crutschow

Well-Known Member
Most Helpful Member
That MOSFET has a large gate input capacitance of 12,000pF and requires the transfer of 236nC of charge to turn it on and off, so you will need a low-impedance gate driver at the output of the opto to operate at 30kHz.
For example,, to achieve a rise/fall time of 1us will require a driver that can source and sink 230mA of current during that transition time.
 

qwertyqwq

Member
That MOSFET has a large gate input capacitance of 12,000pF and requires the transfer of 236nC of charge to turn it on and off, so you will need a low-impedance gate driver at the output of the opto to operate at 30kHz.
For example,, to achieve a rise/fall time of 1us will require a driver that can source and sink 230mA of current during that transition time.

Hmm.
What about a mosfet driver like a ir2110 for output of the optocoupler ?
 

crutschow

Well-Known Member
Most Helpful Member
What about a mosfet driver like a ir2110 for output of the optocoupler ?
That should work, but it is both a high-side and low-side driver.
You might be able to find a cheaper low-side only driver.
 

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