UCC256402: Questions in design about ISNS, VCR and RVCC

Tommy

Part Number: UCC256402

Tool/software:

Hi E2E,

We are designing a product with UCC256402A.

if ISNS, VCR the capacitor CISNS and CVCR(upper & lower) can be designed as follow?
ISNS sampling: C+R+R
VCR sampling: C+R+C

In addition, when the VCC power supply is interrupted, only the HV power supply, Is there still a +12V output by RVCC?

Thanks

10 months ago

0 Mike O' 10 months ago

TI__Guru* 86266 points

Hello,

Your inquiry is under review and I will get back to you shortly.

Regards,

0 Mike O' 10 months ago in reply to Mike O'

TI__Guru* 86266 points

Hello,

In regards to the C + R + C on on the VCR divider, I would recommend against doing this.

The VCR pin was designed to operate off a capacitor divider.

The ISNS pin was designed to work on a C and R divider to sample resonant current. Not sure why you would want to design ISNS into two resistors.

Could you explain this further?

Regards,

0 Tommy 10 months ago in reply to Mike O'

Intellectual 515 points

Hi Mike,

Thanks for help.

we design ISNS into two resistors, It is to avoid the IC being burned out.

what about this question?

Tommy said:
In addition, when the VCC power supply is interrupted, only the HV power supply, Is there still a +12V output by RVCC?

0 Mike O' 10 months ago in reply to Tommy

TI__Guru* 86266 points

Hello,

Your inquiry is under review and I will get back to you shortly.

Regards,

0 Mike O' 10 months ago in reply to Mike O'

TI__Guru* 86266 points

Hello,

Thanks for letting me know. Since ISNS measures a voltage you could use a resistor divider.

The RVCC pin is power by the VCC pin. So if VCC is lost the RVCC will not have a power source and will not be able to provide power to any controllers if VCCs power is lost.

Regards,

Power management

Power management forum

UCC256402: Questions in design about ISNS, VCR and RVCC