TPS55340: no starting

fabrizio montauti

Prodigy 30 points

Part Number: TPS55340

I am pasting this schematic for I need help into turning the Boost die on. I have all voltages at:

VIN=15V

Vout=14.8V

SS=2V

Comp=0.7V

FB=1.64V

EN=5V

SW=15V

No switching at all

boost.pptx

over 5 years ago

0 Yinsong Cai1 over 5 years ago

TI__Expert 7450 points

Hi Fabrizio,

Thanks for your interest in TPS55340.

Could you double check the FB connection? It does not make sense to me.

You have 14.8V output and 1/23 divider but the FB voltage is 1.64V.

Thanks,
Yinsong

0 Youhao Xi over 5 years ago in reply to Yinsong Cai1

TI__Guru* 78070 points

Hi Fabrizio,

I took a look and found Pin 14 and Pin 116 are used wrongly. According to the datasheet, Pin 16 is a SW pin, and Pin 14 is an NC pin. So, in your schematic, you simply shorts the SW to PGND. This may explain your problem.

Thanks,

Youhao Xi, Applications Engineering

0 fabrizio montauti over 5 years ago in reply to Youhao Xi

Prodigy 30 points

Thank you for reviewing it. Sorry, the schematic is wrong but the assembly is correct. we have not gone back to fix the schematic yet.

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TPS55340: no starting