WEBENCH® Tools/LM111: LM111

user6249349

Part Number: LM111

Tool/software: WEBENCH® Design Tools

I want to create a comparator circuit. Negative input gives a pulse(10V&50Hz square waves), positive input constant dc source.Balance & strobe do not needed. Output voltages of upward circuit is always 5V. Output must be change positive & negative input transitions. Can you help me about my mistake.

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi,

like this?

3124.lm111.TSC

Kai

0 user6249349 over 4 years ago in reply to kai klaas69

Prodigy 190 points

my pulse is between -10/+10V. Supplies are -5/18V so i couldn't run it. I understand. Thank you for response. Input limits are important !!!

0 kai klaas69 over 4 years ago in reply to user6249349

Guru 140200 points

Hi,

yes, you must keep an eye on the common mode input voltage range restrictions of LM111 mentioned in the datasheet.

You could use a voltage divider at the input:

lm111_1.TSC

Also think about providing a hysteresis by using a positive feedback loop.

Kai

0 Jonathan Nguyen over 4 years ago in reply to kai klaas69

TI__Expert 4555 points

Hi Kai,

Thanks as always for your help. As Kai showed in his version of the simulation, your output needs to be pulled up to a positive supply, not a negative one to work properly.

His suggestion of using resistor divider to ensure the input is within the common mode range is also a good idea.

Regards,

Jonny

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WEBENCH® Tools/LM111: LM111