ADS7951-Q1: Occasionally, read at 5V and the phenomenon is maintained.

Suhyun Choi

Prodigy 20 points

Part Number: ADS7951-Q1

Hello. I have raised a recent writing a while ago.

I have additional questions.

The phenomenon occasionally reads the ADC output to 5V.

Out applications are BMS(Battery Monitoring System) and system diagram is as follows.

The current sensor output is 2.5V before the relay is operated.

But, At the moment the relay works, the output is sensed to 5V, and the phenomenon is maintained.

(The current sensor output is 2.5V)

It is understood that it is sensed to 5V due to sudden high voltage noise.

However, even when noise disappears, it is not to be understood that the phenomenon is maintained.

I do not know why this happens.

I ask for help.

over 2 years ago

0 Aaron Estrada over 2 years ago

TI__Mastermind 22950 points

Hi Suhyun,

When the relay is switching on, what is the input level at the ADC? Can you specify here? It is possible to capture an oscilloscope shot of the input to the ADC when the relay is switched on?

Regards,

Aaron Estrada

0 Suhyun Choi over 2 years ago in reply to Aaron Estrada

Prodigy 20 points

Hi..

ADC input level is always 2.5V.

But reads as 5V even though it is 2.5V.

0 Aaron Estrada over 2 years ago in reply to Suhyun Choi

TI__Mastermind 22950 points

Hi Suhyun,

Were you able to get an oscilloscope capture of the input to the ADC? I think it would also be helpful if you can also capture the reference input.

Regards,

Aaron Estrada

0 Suhyun Choi over 2 years ago in reply to Aaron Estrada

Prodigy 20 points

Hi,

The BMS(Battery Management System) is placed on the roof of bus.

So capturing with an oscilloscope is difficult.

When the phenomenon occurred, I checked with DVM(Digital Voltage Meter) and the reference voltage at that time

was 2.5V. But ADC reads as 5V.

It is understood that it is sensed to 5V due to sudden high voltage noise.

However, even when noise disappears, it is not to be understood that the phenomenon is maintained.

0 Aaron Estrada over 2 years ago in reply to Suhyun Choi

TI__Mastermind 22950 points

Hi Suhyun,

It is hard to say how the device will behave if there are any violations in terms of max voltage on the inputs/reference/supplies. It's quite possible that the internal protection of the device is getting tripped and somehow latching the device in some unknown state. My advice here is to add some external overvoltage protection to prevent this from happening.

Regards,

Aaron Estrada

0 Suhyun Choi over 2 years ago in reply to Aaron Estrada

Prodigy 20 points

Thank you for your opinion.

I look for another method for troubleshooting.

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ADS7951-Q1: Occasionally, read at 5V and the phenomenon is maintained.