TPS55165-Q1: TPS55165-Q1 Can't be Turned On

user5791980

Part Number: TPS55165-Q1

Hi,

We are using TPS55165-Q1 for one of our applications. The schematic is based on Webench. The input voltage is between +8 to +18 V and the output is +12V. The IGN pin is controlled by a processor with +5V output. The PS, ING_PWRL, SS_EN and PG_DLY are all connected to ground. The VOS_FB is conected to VREG and VREG_Q, which connected to ground through two 4.7uF capacitors. When the +5V was applied to IGN pin, the TPS55165-Q1 is not responding. Based on the datasheet, the +5V should be enough to turn on the TPS55165-Q1. Thank you.

Best Regards,

Chun-Te Li

over 6 years ago

0 user5791980 over 6 years ago

Prodigy 140 points

The schematic of TPS55165 is attached.

Schematic_TPS55165.pdf

0 Helen chen over 6 years ago in reply to user5791980

TI__Mastermind 40080 points

Dear Sir,

I need to check the pcb to check whether the layout is OK!

0 user5791980 over 6 years ago in reply to Helen chen

Prodigy 140 points

HI,

Please see the attached file. The red color is top level and blue color is bottom level. We only use two layer board. Thank you.

Best Regards,

Chun-Te LiTPS55165_PCB_Layout.pdf

0 Helen chen over 6 years ago in reply to user5791980

TI__Mastermind 40080 points

Dear Sir,

The layout is too poor.C10, C13, C15 should be very carefully placed.

Please follow the attached file page2 for their placement and the layout. 3884.Layout.pptx

0 user5791980 over 6 years ago in reply to Helen chen

Prodigy 140 points

Hi Helen,

Thanks for the advice. We will update the layout. Meanwhile, the IC, for some unknown reason, starts to show activity. However, the output voltage is not what we expected. I have attached files for the scope screen shot of V_output, V_inductor and Vreg. Please provide any feedback ton why the output is not what we expect. Thank you.

Best Regards,

Chun-Te Li