TPS54294: output stop at high voltage output

PAN-M

Part Number: TPS54294

Dear all.

1. Vin=10.8V, Vout1=5.5V/100mA, Vout2=3.7V/1.5A
2. Vin=10.8V, Vout1=5.2V/100mA, Vout2=3.7V/1.5A

The output appears with case 2, but both output stops with case 1.
This circuit modified EVM.
3.7V : L=3.3uF 5.5V : L=4.7uF
Is the value of the inductor appropriate?

What Is the point to be careful about when I up the output voltage close to maximum duty?

Regards,
PAN-M

over 6 years ago

0 Edwin Zang over 6 years ago

TI__Expert 6425 points

Hello Pan,

I'm a litter confused about your question. what do you mean output stops with case 1?

the ductor you changed looks well. do you change other comonent?

best regards

edwin.

0 PAN-M over 6 years ago in reply to Edwin Zang

Mastermind 8375 points

Our customer use EVM for confirmation of the output.
They change feed back resistance and inductors.
They change feed back register for target output.
It is not both output when they make setting of the output voltage 5.5V of output1.
But it can both output when they make setting of the output voltage 5.2V of output1.

Why will such a phenomenon happen?

Regards,
PAN-M

0 Jason Wang (BSR-MV) over 6 years ago in reply to PAN-M

TI__Genius 9550 points

Hi,
the schematic/setup is ok for case 1. Can't fingure out why no output for case1 from the information you mentioned. Suggest you can support customer on site and check the solder quality and real setup.

0 Edwin Zang over 6 years ago in reply to PAN-M

TI__Expert 6425 points

Hello Pan,

1, what value of resister and inductor you change to?

2, can you upload SW,Boost waveform when it is not both output.

best regards

edwin,.

0 PAN-M over 6 years ago in reply to Edwin Zang

Mastermind 8375 points

Yes, I will check inductor spec to customer.
Also, I will check output capacitor(DC bias spec: EVM is 6.3V) and input source.
Regards,
PAN-M

Power management

Power management forum

TPS54294: output stop at high voltage output