Simple level shifter to convert 12 V to 3.3 V suitable for MSP432

michaelwu

Other Parts Discussed in Thread: TLV7211, LM393, CD40109B

Hi,

In my application, I need a falling edge detector that can take high-voltage inputs (up to about 12 V or so). Therefore, I'm looking into using TLV7211 as the comparator of choice. This means that the digital output will be around 12 V or so, but I need to step this down to 3.3 V to interface properly with my microcontroller, the MSP432.

Does TI have any solutions for this? I used the online tool to take a quick look down the portfolio of unidirectional voltage shifters, but it looks like none of the devices are 12 V compatible. Thanks!

Regards,

Michael

over 5 years ago

0 Sally Cheung95 over 5 years ago

TI__Expert 5480 points

Hi Michael,

You can use the LM393 for those voltage specs and you could set the Vpull up to be 3.3V. However, are you only looking for it to trip at the falling edge because these devices do not work unilaterally. There are other parts in the TI portfolio that you may browse around to find.

Thanks,

Sally

0 Chuck Sins over 5 years ago

TI__Mastermind 25990 points

Michael

Do you have any speed requirements for your falling edge detector?

Comparators that have open-drain or open-collector outputs are frequently used to level shift signals to satisfy low voltage input devices.

Chuck

0 ShreyasRao over 5 years ago

TI__Guru 62180 points

Hi Michael,

You could consider using the CD40109B which supports 3V to 18V level shifting.

I have filtered the voltage level shifters here

0 Chuck Sins over 5 years ago in reply to ShreyasRao

TI__Mastermind 25990 points

Thanks Shreyas for providing some options for Michael.

Michael

The options that Shreyas provided are 4-channel and 6-channel options.

If you need less channels, potentially only 1 channel, a comparator might be a good option for you still.

Please let us know if you have any speed requirements for your falling edge detector so we properly assess.

Thanks

Chuck

0 michaelwu over 5 years ago in reply to Chuck Sins

Intellectual 460 points

Hi Chuck and Shreyas,

Thanks for your suggestions. I did some thinking over the past couple of days and realized there were some implementation issues for the problem I've described. I've gone another route with solving the problem which uses a more straightforward approach.

Regards,

Michael

Logic

Logic forum

Simple level shifter to convert 12 V to 3.3 V suitable for MSP432