Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 1005 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DCP010505B: DCP010505B start up Current

Lei wang
Expert 1620 points
Part Number: DCP010505B
Other Parts Discussed in Thread: DCPA10505

HI sir:

    When i use the DCP010505B for a 60ma load. i find that when I start up .i will be have a big current. And about 5s later it will be normal. I use it refrence the datasheet.

  • 0
    TI__Mastermind 38230 points

    Lei:

    Request  your  complete schematic for the DCP010505BP including Vin input and output  capacitors type and capacitance value. location of input capacitors.

    1A.Is the DCP010505 Sync. On/off pin, pin14 used to control the on-off function is it open/ no connection>

     

    2. t what is the 5V input power source DCP010505BP, current rating and inrush current rating?

    2a. When the initial input power is applied does the output voltage t is possible the  DCP010505 input inrush current is  loading down its input 5V power source.  

    2b.   Place Scope probe on  the DCP010505BP input power source  What is the DCP010505BP Vin 5V input data characteristics  during power up mode?

    2c.  Is the  5Vin voltage dropping below 4V during initial power up.

    Tom

  • 0 in reply to Tom Guerin
    Expert 1620 points

    1.no connection

    2.the U19 Lm1117-5V  is 1A output for DCP010505BP (2 DCP+200ma U20 LDO LM1117-3.3). input current for DCP is about 400ma.

    3.Is the  5Vin voltage dropping below 4V during initial power up. Yes .it will below 3V somtimes.

  • 0 in reply to Lei wang
    TI__Mastermind 38230 points

    Hi Lei:

    anks for the schematic of the DCP010505,

     Based upon your data comment It appears there  are (2) DCP01050 on the 5V input power source(M1171-5V) including LM1171-3V3

    Based upon  your data comment , It appears there  are (2) DCP01050 on the 5V input power source(LM1171-5V) including LM1171-3V3out voltage .

    1. Regarding your C172 0.1µF(104 value)( change to 2.2µF and located very close to the DCP010505BP.

    A,. DCP010505  series required minimum input ceramic capacitance  is 2.2µF . 2.2µF ceramic capacitor  is be located very close to and between input Pin1 ( Vin(+) and pin 2( Vin(-)

    Input inrush current during startup period can over load input 5V power LM1171-5V) drooping the input voltage to below 4V.

    See below  for spec.DCP010505 details on inrush current

     

     

    2. There is another direct replacement converter , 1W, DCPA10505P available with reduced soft start-up in-rush current. Same package type and same pins functionality It is a direct drop in replacement for the DCP010505BP.

    Tom

  • 0 in reply to Tom Guerin
    TI__Mastermind 38230 points

    Lei

    The DCPA10505 link is

    Tom