# Calculating the voltage difference between a switching pin out and a constant Vout

#### Electronic_Maniac

Joined Oct 26, 2017
251
Hi all,

Sorry to trouble you all with a similar question. But this is a different question altogether regarding calculation of voltage difference.
I am using this NCV3063 IC.

According to my design of the boost converter in my board, I am measuring the values of Pin1 and pin2 in multimeter and scope respectively. This is a reference board. For Vin(Vcc) of 16V, The voltage at pin1(SWC) of the IC is 5.05V as measured in DMM. (1)
Pin2 (SWE), I am measuring in scope, I am getting a peak-peak of some 15.8V with 30.6% duty and Max amplitude of 13.8V. (2)
Now, Vswce=difference between the pins 1 and 2. How to calculate the voltage difference between (1) and(2) ?
Or in general, how to calculate the voltage difference between a switching Vout pin (in this case, pin2) and a constant Vout pin (in this case, pin1)

Thanks

#### MrSoftware

Joined Oct 29, 2013
1,610
Do you want to know the peak difference, the RMS difference or the average difference? What is your goal?

• Electronic_Maniac

#### Electronic_Maniac

Joined Oct 26, 2017
251
Do you want to know the peak difference, the RMS difference or the average difference? What is your goal?
Can you tell me how to calculate each one?

#### Danko

Joined Nov 22, 2017
842
• MrSoftware

#### MrSoftware

Joined Oct 29, 2013
1,610
The easy way out is to use a scope that can give you all 3 without having to do the math. What is it that you are trying to do?

• Danko

#### Danko

Joined Nov 22, 2017
842
Or in general, how to calculate the voltage difference between a switching Vout pin (in this case, pin2) and a constant Vout pin (in this case, pin1)
You can exclude subtraction operation, simply putting ground clip to pin1 and probe to pin 2.
You will see exactly what you trying to find.

Last edited:

#### Electronic_Maniac

Joined Oct 26, 2017
251
You can exclude subtraction operation, simply putting ground clip to pin1 and probe to pin 2.
You will see exactly what you trying to find.
yes thanks. But How do I calculate in theory the voltage difference between a switching node and a constant output node?

#### Danko

Joined Nov 22, 2017
842
• Electronic_Maniac