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  • TI Thinks Resolved

WEBENCH® Tools/TPS55165-Q1:

Prodigy 90 points

Replies: 14

Views: 360

Part Number: TPS55165-Q1

Tool/software: WEBENCH® Design Tools

Hi TI Team, 

the manual of the TPS55165-Q1 shows an application for the 12V-fixed version in which the PG Pin is connected to an external 5V power supply via an 100kOhm resistor. 

I have this setup on my PCB and the output only BUCK-BOOSTs to 10V at 6V to 14V input and only BUCKS to 12V at 15V input.

In contrast to that, the WEBENCH tool suggests that the PG Pin should be connected to Vout = 12V.

Which configuration is the right one?

Thanks in advance 

Franz Braun

  • Link to the configuration as suggestet by WEBENCH:

    webench.ti.com/.../2

  • In reply to Franz Braun:

    Hi Franz,

    The device can have  only two outputs 5V and 12 V. I checked with the simulation results for the conditions shared by you and they are working fine.

    Since you are testing on board, we have asked concerned expertise to answer your query.

    Thanks and Regards,

    Atul

  • Dear Sir,

    Could u please post your sch and the pcb layout? I want to check the parameter and the pcb layout.

    Best Regards,
    Helen

    Boost DC/DC Solution

  • Dear Sir,

    Could u please post your sch and the pcb layout? I want to check the parameter and the pcb layout.

    Best Regards,
    Helen

    Boost DC/DC Solution

  • In reply to Helen chen:

    Dear TI Team, 

    this is my sch of the PCB: 

    The brd is the following: 

    As I've mentioned, the difference in my PCB is, that I have connected the PG Pin to the external 5V source as shown in the manual page 30, Fig.24. But unfortunately the WEBENCH layout differs from that by showing a connection of Vout to PG. 

    So therefor I'm a little confused, if my PCB should actually work?

    Many Thanks in advance

    Franz Braun

  • In reply to Franz Braun:

    Thank you for the update, I'll review it in detail and reply you tomorrow!

    Best Regards,
    Helen

    Boost DC/DC Solution

  • In reply to Helen chen:

    Hi Helen,

    thank you for the effort. Probably I should give you same more information to make it easier for you to evaluate my PCB: 

    - When I'm slowly increasing the voltage from 5V to 10V my output voltage is about 9V. From 11V and more, my output voltage is about 10V. So maybe there is a problem with the feed back.

    - I have chosen 1uF instead of 0.1uF Boot-Strap capacitors. Maybe they cannot charge completely since the frequenzy and capacitance is too high? 

    - The use or non-use of SS_EN doesn't change anything. 

    - The IGN_PWRL can be connected to the MSP430, an external 3V3 source, or left open floating. It also doesn't change a thing. 

    - The PS Pin is connected to GND. 

    I hope this info can help you. 

    Best 

    Franz Braun :-)

  • In reply to Franz Braun:

    Dear Sir,

    The sch is OK. But the pcb layout is poor.

    1. They need to take care of the layout of C30, C35, C36. Please refer to the attached ppt page 2 for a reference;

    2. The PGND connection is very poor. Pin1 and Pin18, Pin13  need to connect to the thermal Pad to realize a single point of AGND and PGND. They pour a whole a copper plane at the top layer and the bottom layer.

    After the relayout. Please send the pcb to us for a review again.

    Best Regards,
    Helen

    Boost DC/DC Solution

  • In reply to Helen chen:

    Best Regards,
    Helen

    Boost DC/DC Solution

  • In reply to Helen chen:

    Best Regards,
    Helen

    Boost DC/DC Solution

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