TPS56C215: OCL function issue

CHEN YAN

Intellectual 1430 points

Part Number: TPS56C215

Hi,

My customer meets an issue about OCL function of TPS56C215-EVM:

Vin=5V;

Vout=1.8V(R7=20K);

L1=680nH；

Mode：（R5=51K，R4=91K）

When the Load change from 2A to 12A，the OCL waveform is different from the discription of datasheet.（CH1：Iout；CH2：Vin；CH3：Vout）:

datasheet: When the output voltage lower at 68% of initial voltage, the UVP is on, and turn off the device after 1ms.

Then after 7ms's hiccup mode, reset the device, and the test waveform didn't show it.

Could you please help me figure out the reason behind? Thanks.

The following two test waveform: CH1：Iout；CH2：Vin；CH3：Vout

This is the waveform of SW pin.

over 5 years ago

0 Edwin Zang over 5 years ago

TI__Expert 6425 points

Hi Yan,

1, According to your mode selection, OC valley is 11.5A. The ripple in your circuit is 2.12A. If you change a 12A loading, the Valley of inductor current is about 10.94A. It couldn't make IC happen OC protection. From your waveform, loading is less than 12A. I don't think it trigger IC OC protection. If you want to test OC, please use larger loading, such as 15A. Or you can directly hard short Vout.

2, Please check power supply whether it can support 12A loading. The loading line should be enough short.

BRs,

Edwin.

0 CHEN YAN over 5 years ago in reply to Edwin Zang

TI__Intellectual 1430 points

Hi Edwin,

Sorry for the mistake about my description, the actual load is from 2A to 20A.

Best Regards.

0 Edwin Zang over 5 years ago in reply to CHEN YAN

TI__Expert 6425 points

Hi Chen,
let's discussed it by email.
I close this.
Thanks a lot.

Power management

Power management forum

TPS56C215: OCL function issue