TPS659037: GPADC Conversion Time

Kuramochi Tadahiko

Guru 28715 points

Part Number: TPS659037

Hi,

My customer is evaluating the TPS659037 and GPADC function.

ADC conversion finishes on 150us normally, though it takes over 1ms at high temperature condition(over 60℃).

Is it common behavior?

Best Regards,

Kuramochi

over 5 years ago

0 Nastasha over 5 years ago

TI__Genius 10000 points

Hi,

I have not observed the GPADC conversion be dependent on device temperature. What channels are you measuring in the GPADC?

Thanks,

Nastasha

0 Kuramochi Tadahiko over 5 years ago in reply to Nastasha

Guru 28715 points

Hi,

Thank you for your reply.

We monitor the battery voltage with the resistor divider by GPADC_IN1.

Best Regards,

Kuramochi

0 Nastasha over 5 years ago in reply to Kuramochi Tadahiko

TI__Genius 10000 points

Kuramochi-san,

Hi, as long as the resistor divider keeps the voltage below 1.25V, I do not see any reason why this implementation would vary in conversion time over temperature. What is the effective resistance of the voltage divider at hot temp? Could the voltage be exceeding the limit?

Thanks,

Nastasha

0 Kuramochi Tadahiko over 5 years ago in reply to Nastasha

Guru 28715 points

Hi Natasya-san,

I verified above by mistake...

CPU readouts the ADC data every 1ms, however, interrupt() does not returns at high temperature within 1ms.

What can we consider as the reason?

Best Regards,

Kuramochi

0 Nastasha over 5 years ago in reply to Kuramochi Tadahiko

TI__Genius 10000 points

Kuramochi-san,

Okay, I see. I think this makes sense. Thanks for confirming.

Regards,
Nastasha

0 Kuramochi Tadahiko over 5 years ago in reply to Nastasha

Guru 28715 points

Nastasha-san,

Thank you for your reply.

What is the cause of the delay of interrupt?

Best Regards,

Kuramochi

0 Kevin LaRosa over 5 years ago in reply to Kuramochi Tadahiko

TI__Genius 17380 points

Hi Tadahiko-san,

Could you help to provide a scope shot of the I2C writes to start the conversion and the rising of the interrupt on the same scope shot as well as zoomed in images of the I2C writes?

Since we have not seen this happen before we would like to check on whether there is any abnormal appears in these.

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TPS659037: GPADC Conversion Time