Sensors中的主题 Re: ADC Calibration Equation

ADC Calibration Equation

xgy_upc — Tue, 28 Jul 2020 09:09:22 GMT

In AN3949 --ADC16 Calibration Procedure and Programmable Delay Block Synchronization, there are two formulae, one for single-terminal input and the other for differential input.

Is this formula the gain scaling formula after ADC conversion? Is Code the value stored in the result register after gain scaling?Where do the capacitance values Cs and Cn come from?

Re: ADC Calibration Equation

Alexis_A — Thu, 30 Jul 2020 15:58:06 GMT

Hello,

Can you let me know which MCU are you using?

Best Regards,

Alexis Andalon

Re: ADC Calibration Equation

xgy_upc — Fri, 31 Jul 2020 01:59:07 GMT

I'm using KV31F512VLL now

Re: ADC Calibration Equation

Alexis_A — Fri, 31 Jul 2020 20:35:22 GMT

Hello,

The application note that you're pointing to is from an old MCU, for this MCU the module already has a function for calibration. If you check in the reference manual the chapter 32.4.5 Calibration function, you could check the details of this feature.

Best Regards,

Alexis Andalon

Re: ADC Calibration Equation

xgy_upc — Sat, 01 Aug 2020 14:24:50 GMT

Dear Alexis Andalon,

I have read the KV31 reference manual about the calibration function.I think the old MCU in the application notes is basically the same as the ADC calibration of KV31.I just want to know what those two formulas mean in detail

Best Regards,

Re: ADC Calibration Equation

Alexis_A — Mon, 03 Aug 2020 17:11:15 GMT

Hello 相国尹,

The nominal capacitance will be the ideal capacitance need it to match the sample and the sampled one will be the input capacitance that you can check in the datasheet.

The gain value will be as the next figure show, the multiplication value after the conversion to match the ideal sample.

Best Regards,

Alexis Andalon

Re: ADC Calibration Equation

xgy_upc — Tue, 04 Aug 2020 13:15:03 GMT

So,Is this formula the gain scaling formula after ADC conversion? Is Code the value stored in the result register after gain scaling?

Re: ADC Calibration Equation

Alexis_A — Tue, 04 Aug 2020 16:22:30 GMT

That's right, the code value is the one that should be stored in the register but as I previously mentioned, you don't need to worry about this calibration since the auto-calibration does this.

Best Regards,
Alexis Andalon