S12ZVCA192 BATS measurement

[vase8890]

hello:

Now I have a problem with VSUP measurement. When the BATS voltage exceeds 16V, the BCTL and BCTLC voltage changes, and the ADC measurement of VSUP is wrong.

When BATS is 17V, BCTLC and BCTL are measured to be about 6V, and VSUP is about 14V.Why is that?

I think my configuration is wrong, but I did not find the other configuration place, how to solve it?

BR!

[danielmartynek · Accepted solution]

Hello @vase8890,

I'm not sure if I understand.

VBATS equals to VSUP.

And you say that VBATS = 17V while VSUP = 14V.

Can you please elaborate?

What ballast PNP transistors do you use?

Can you please share the schematic?

Thank you,

BR, Daniel

[vase8890]

Yes, you're right

VBATS equals to VSUP

When I increased the VBATS voltage to 17V, the ADC measurement value was 15.6V, the multiple: 9

BCTL and BCTLC are around 5.6, not 5V anymore

Circuit shown in the following：

if 30F_IN=16V or 30F_IN=12V It is a good

It's not accurate when it's larger than 17 V

[danielmartynek]

Thanks @vase8890,

So, VDDA (VRH_1 ADC voltage reference) is also 5.6V?

I think this would explain the incorrect measurement.

Did you disable the internal ballast transistor (CPMUVREGCTL) ?

BR, Daniel

[vase8890]

Yeah I think disable the internal ballast transistor！

I also think the reference voltage has changed！

But  Why？

That's why I'm confused

[danielmartynek]

Can you please remove the C22, C25 capacitors?

And test it again?

Thank you,

BR, Daniel

[vase8890]

Thank you very much for your reply.

I have found the problem, because the PCB packaging is wrong!I changed the packaging problem solved!

Thank you so much!

[vase8890]

I have removed the C22  C25 capacitors

But it did not improve！

I found that the MCU would be hot, but the program was running fine!

Do you suspect a hardware problem? 

now I'm going to try it out with an internal ballast！

[danielmartynek]

Hello @vase8890,

Can you please measure the consumption of the MCU?

Do you drive any loads by the GPIOs?

Thank you,

BR, Daniel

[vase8890]

Thank you very much for your reply.

I have found the problem, because the PCB packaging is wrong!I changed the packaging problem solved!（PNP）

Thank you so much!

BR！