TPL5010: TPL5010 ADC period calcualtion

Mohamad Nizar Kezzo

Part Number: TPL5010

In the TPL5010 datasheet, it states that a quantization error can be calculated using the relationship mentioned in section 8.5.4 (page 13):

I am trying to find out exactly what the function INT stand for in the calculation. I tried to re-run the calculations in the example assuming INT stood for Integer, for Interval, and for Integral, but to no avail. Can you please provide a more helpful explanation of the calculation.

Best,

Nizar

over 7 years ago

0 Tim Chao Li over 7 years ago

TI__Expert 4415 points

Hi Nizar,

You are correct, INT is the Integer function, which is essentially rounding down (for example, given 3.9, INT[3.9] = 3). The quantization error is a result of the device 'rounding' to the nearest discrete timer interval when it reads Rext.

Is there a specific use case that you need to calculate quantization error for?

Regards,

-Tim

0 Mohamad Nizar Kezzo over 7 years ago in reply to Tim Chao Li

Prodigy 175 points

Thanks for the answer!
-I am only using the DONE signal on TPL5010. The WAKE signal is left unconnected due to limited GPIO count on the MCU.
-For this reason, I need to feed the DONE signal at a minimum of twice the frequency of the WAKE signal (i.e. at most half the Time Interval Period, t_ip).
-Thus, I need to calculate the worst case frequency (highest frequency, or lowest period). This is done by taking the resistor error and the quantization error into my calculation of the period.

This post explains my intended implementation:
e2e.ti.com/.../609116

0 Tim Chao Li over 7 years ago in reply to Mohamad Nizar Kezzo

TI__Expert 4415 points

Hi Nizar,

That should work. To ensure that you get more than twice the frequency, you could even use the frequency corresponding to the timer interval that is one faster than the one you intend to set.

Regards,

-Tim

0 Mohamad Nizar Kezzo over 7 years ago in reply to Tim Chao Li

Prodigy 175 points

I see. Thanks!

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TPL5010: TPL5010 ADC period calcualtion