LMP92064 negative differential voltage on current sense

Xavier Bernard

Prodigy 200 points

Other Parts Discussed in Thread: LMP92064

Hi,

I was wondering if the LMP92064 could sense something on its differential current sense inputs with this voltage range:

INCP pin: -60mV - 0V

INCN pin: 0V (GND)

Knowing that the minimum Vcm of the inputs is -200mV, it is not dangerous for the chip.

It is also possible for me to make it like that:

INCP pin: 0V (GND)

INCN pin: -60mV - 0V

Is the internal circuitry of the LMP92064 still capable of sensing the difference between the two inputs, even if one of those is negative?

Thank you!

over 9 years ago

0 Jason Bridgmon over 9 years ago

TI__Genius 14825 points

Xavier,

Thank you for your question, we'll respond shortly.

Best regards,

Jason Bridgmon

0 Sergio over 9 years ago

TI__Expert 3835 points

Hello Xavier,

The LMP92064 is unidirectional and cannot sense negative differential voltages across its pins... the digital output will clip to zero.

There is no problem with the proposed common-mode range... -60 mV is well within its -200 mV lower range of Vcm. However, you would have to sense this as you suggest in your second option: INCP at 0 V (GND) and INCN at -60 mV.

Best regards,

Sergio

0 Xavier Bernard over 9 years ago in reply to Sergio

Prodigy 200 points

Sergio,

Thank you very much, it is a nice workaround.

Best regards,

Xavier

0 Sergio over 9 years ago in reply to Xavier Bernard

TI__Expert 3835 points

You are welcome.

Best regards,

Sergio

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LMP92064 negative differential voltage on current sense