• State TI Thinks Resolved
  • Locked Locked
  • Replies 11 replies
  • Answers 1 answer
  • Subscribers 65 subscribers
  • Views 179 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.

LM5064: TIMER Pin issue

Tommy Tzeng
Genius 5290 points
Part Number: LM5064

Tool/software:

Hi Team,

attached is the schematic and i2c setting command of LM5064. 

it can start normally when it is power on, it will restart when other devices plugged in after turn it on. and when thr Timer waveform reach 3.9v, the MOS is turned off,

what could be cause this? 

thanks for your help and learn from you.

0574.LM5064 circuit.pdf

LM5064.txt 
~ # i2cdump -y -f 8 0x16
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: XX 80 XX ff XX XX XX XX XX XX XX XX XX XX XX XX    X?X.XXXXXXXXXXXX
10: XX XX XX XX XX XX XX XX XX b0 XX XX XX XX XX XX    XXXXXXXXX?XXXXXX
20: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
30: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
40: XX XX XX 00 XX XX XX XX XX XX XX XX XX XX XX 60    XXX.XXXXXXXXXXX`
50: XX d0 XX XX XX XX XX ff 00 XX XX XX XX XX XX XX    X?XXXXX..XXXXXXX
60: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
70: XX XX XX XX XX XX XX XX 03 03 00 XX 04 00 82 XX    XXXXXXXX??.X?.?X
80: 10 XX XX XX XX XX XX XX be XX XX b0 XX e7 XX XX    ?XXXXXXX?XX?X?XX
90: XX XX XX XX XX XX XX XX XX 03 08 02 XX XX XX XX    XXXXXXXXX???XXXX
a0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
b0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
c0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
d0: ff ba 45 ff ff 33 ff 09 00 00 0c 0c be b0 bd 46    .?E..3.?..?????F
e0: 0c 8a 0c XX XX XX XX XX XX XX XX XX XX XX XX XX    ???XXXXXXXXXXXXX
f0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
~ #

  • 0
    TI__Guru** 104981 points

    Hi Tommy,

    You mean the LM5064 is turning off the hot-swap FET when other loads are hot-plugged at the output of LM5064. It can be due to high transient current of connected loads.

    Can you share test waveform of input current, TIMER, GATE and OUT pin voltages ?

     

    Regards,

    Rakesh

  • 0 in reply to Rakesh
    Prodigy 110 points

    below picture is LM5064 turn off the hot-swap FET when other loads are hot-plugged 

    red line: output

    green line: gate

    yellow line: TIMER

    This waveform like insertion delay, but it should be fault timer when normal working, right?

    Another question,  MFR_SPECIFIC_17: READ_DIAGNOSTIC_WORD (E1h) value is 8a, but how to  transform to 16 bits?

    1050.LM5064 circuit.pdf

  • 0 in reply to ?? ?
    TI__Guru** 104981 points

    Hi Tommy,

    The device is hitting short-circuit threshold when you do load hot-plug and then turning-off. Probably SENSE_ K and SENSE pins are going below negative during turn-off

    Please use Schottky diodes as shown in Figure 17 of the data sheet and test again. 

    BR,

    Rakesh

  • 0 in reply to Rakesh
    Prodigy 110 points

    Hi Rakesh:

    Current waveform as below, it has about 1.68A when gate pull low.

    Our curent limit is 12.5A.  Circuit Breaker threshould is 12.5*3.7=46.25A. So it seems not like Circuit Breaker.

    Tim

  • 0 in reply to ?? ?
    Prodigy 110 points

    Hi Rakesh:

    How to use CLEAR FAULTS (03h)? I try write 0xff or 0x00, but it's no use.

    Does READ_DIAGNOSTIC_WORD (E1h) show 088a correct after power up?

  • 0 in reply to ?? ?
    Prodigy 110 points

    Hi Rakesh:

    I use CLEAR FAULTS (03h) to clear READ_DIAGNOSTIC_WORD (E1h).

    After hotswap other loads and gate turn-off about 120ms, then read READ_DIAGNOSTIC_WORD (E1h) is 080a.

    It mean Iin OC occur, but there has no fault timer waveform on CT. Is it possible that LM5064 is broken?

  • 0 in reply to ?? ?
    TI__Guru** 104981 points

    Have you tried by adding Schottky diodes as shown in Figure 17 of the data sheet ?

  • 0 in reply to Rakesh
    Prodigy 110 points

    Hi Rakesh:

    Yes, We have add 2 diodes as below.

    Tim

  • 0 in reply to ?? ?
    TI__Guru** 104981 points

    Hi Tim,

    I am mentioning about the diodes circled in the below image

    Best Regards,

    Rakesh

  • 0 in reply to Rakesh
    Prodigy 110 points

    Hi Rakesh:

    So You mean ic maybe brokean after hot-swap loading without diodes on these sense pin?

    Then read ic status will not match waveform? because there have no fault timer in over current event, Is my explanation correct?

    Tim

  • 0 in reply to ?? ?
    TI__Guru** 104981 points

    yes Tim.

    For hot-swap loading, the device triggers overload and cut-off the high current abruptly. This leads to negative voltage transient on these pins and resets the device.

    For shot-circuit event, fault timer would not respond. So, most probably the device is hitting short-circuit for hot-swap loading

    BR,

    Rakesh