Comparator+Latch

Giora Eytan

Expert 1305 points

Other Parts Discussed in Thread: TLV7021

Hello,

I am looking for a design of a comparator with a latched output.

Meaning when the input reaches a certain threshold, the comparator change a state ( from 0V to high for 5V for example)

and stays - (latched) - to this until power down.

Giora

over 5 years ago

0 Joe Vanacore over 5 years ago

TI__Mastermind 18975 points

Hi Giora,

I would like to know a little more about your design requirements. Are you looking for a comparator with a latch-enable pin? Or are you looking for a circuit that achieves a latched output state via external components?

Also, what are your desired specifications for the device? (Supply Voltage, push-pull output...etc.)

Thanks,

Joe

0 Giora Eytan over 5 years ago in reply to Joe Vanacore

Expert 1305 points

Hi Joe,

Thanks.

I need a comparator that his output is latched when its input reaches some threshold or has you stated :

a circuit that achieves a latched output state via external components?.

Should work from 5V supply and it has open collector output.

Giora

0 Clemens Ladisch over 5 years ago

Guru 321460 points

This can be implemented with a comparator with a very large hysteresis. Just set the negative-going threshold to a negative value. For example, with a 5 V supply and thresholds of 4 V and −1 V, you have to use equal resistors (R2/R1 = 1) and V_REF = 2 V.

0 Giora Eytan over 5 years ago in reply to Clemens Ladisch

Expert 1305 points

Clements,

Can you send a sketch?

What comparator do you recommended?

Giora

0 Clemens Ladisch over 5 years ago in reply to Giora Eytan

Guru 321460 points

See any comparator hysteresis calculator, for example, daycounter.com/Calculators/Comparator-Hysteresis-Calculator.phtml.

Serch for rail-to-rail 5 V open-drain comparators, e.g., TLV7021.

0 Joe Vanacore over 5 years ago in reply to Clemens Ladisch

TI__Mastermind 18975 points

Thank you for the support Clemens!

Giora, I hope that this was the information you were looking for.

Thanks,

Joe

0 Giora Eytan over 5 years ago in reply to Clemens Ladisch

Expert 1305 points

Thanks.

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Comparator+Latch