UCD3138064: Combine 2 ADCs to double the sense range

Hello Jack

Unfortunately not, there is only one ADC on the UCD3138, and it can only digitize voltages up to 2.5V. The absolute max ratings on the ADC input pins is 3.8V as per the datasheet.

Your only option is the divide down the input signal so it has a max value of 2.5V. 

Kind Regards

Cormac

Hello Jack,

It may be too simple of a question, but why don't you use a voltage divider to attenuate the 5V?

Regards,

Hello Jack,

Do you use it for current sharing? thanks.

Hi Expert,

 - Because I want the resolution.

I'm using ADC for max 332A output current sensing, however, there is an around 200mV ripple on the signal, which correspond to 26.56A. I can't add too much capacitor to filter it since there is timing concern. Therefore, I want to double the range to ease the ripple issue.

Hi Han,

 - It's for peak power detection. The rated output power is 2000W (166.6A), and Pmax peak current needs extra 120A, which is total 286.6A. However, there is about 200mVp-p ripple on the Iout sense signal (I think it's because of the EMI interference), and the Peak current detection needs to be within 5~20us, so we can't add too much capacitor.

 - We are thinking about adding a differential to the second ADC for second level current sense.

You do not loose resolution by using a voltage divider. The resolution will stay exactly the same.