TPS54202: TPS54202 EN PIN add Cap question

Hi ,

It's okay to remove resistors here. for the cap, what's the value of it ?

BRs,

Young

Hi Young, 

Thanks for reply

The Cap is 10nF 

Hi Young, 

After implemented the 10nF in EN pin, my customer found another issue that VOUT will startup non-smoothly after discharge the 10nF cap (cold start)

do you know the reason?

the countermeasure right now is addition upper 240Kohm and bottom 100Kohm to resolve it 

any side effect w/ this change?    

CH1 is VIN 

CH4 is VOUT

Hi,

Could you also capture EN and SW pin waveform (+VIN+Vout)?

BRs,

Young

Hi Young

Hi,

I didn't see the non-smoothly Vout here. They are tested with EN resistor ?

BRs,

Young

Hi Young, 

it's very difficult to capture the EN pin in this condition even used differential probe  

but the symptom is quit similar, the VOUT (PVCC) will delay start up and ramp up slowly 

since this case is urgent, may we off line discuss this case by phone call around noon?

Hi ,

The reason for the delay is because of internal current will charge EN pin cap till Enable threshold to get device enabled .

for the non-smoothly, it may related with the loading . We can communicate offline young-Zhao@ti.com

BRs,

Young