LM311: LM311 output connected to optocoupler

TTG tt

Prodigy 170 points

Part Number: LM311

Dear team, the output of LM311 is connected to the optocoupler circuit as shown in the figure below.

Is this circuit correct?

What is the proper range of LM311's transistor ICE.

What is the saturation voltage drop VCE(SAT) of the triode?

What is the range of VCE.

Thank you.

over 4 years ago

+1 kai klaas69 over 4 years ago

Guru 140200 points

Hi ttg,

whether this circuit is correct or not cannot be said without knowing the used optocoupler. Optocouplers come in very different current transfer ratios and need different input control currents.

You might want to read this:

application_note_en_20180201.pdf

Kai

+1 Chuck Sins over 4 years ago in reply to kai klaas69

TI__Mastermind 26300 points

Thanks for post. As Kai mentioned, it is safest for you to provide info about the optocoupler to confirm it is connected correctly.

But in general, it looks like you have connected correctly. Nodes 1 and 2 either get shorted to ground through the output of the comparator or they are in a high Z state.

Chuck

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LM311: LM311 output connected to optocoupler