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TIDA-01494: TIDA-01494

Seongwoong kim
Intellectual 480 points
Part Number: TIDA-01494
Other Parts Discussed in Thread: UCC28180, UCC256303, UCC256301, TIDA-00779

Hi,

We are developing the SMPS based on the TIDA-01494

R27 and R25 is not connected. 

What's the functions of the resistors. ? 

If there is no resistors, is there no problem.. ?

At the moment that ac power is on and off, aux_15 line is short. 

Why did that happen?

UCC25630 does not work. so it was replaced by a new chip UCC25630 

but it' not working. 

Where is the problem.. ?

Thanks

Regards,

Nick. 

  • 0
    Intellectual 480 points

    Fuse (8A) and Q1 is broken whenever the power is off and on

    under the conditions that the 24V output power and aux 15 and aux_iso 15 is alive 

    Would you check ?

  • 0 in reply to Seongwoong kim
    Intellectual 480 points

    I know that The PFC_Off is not working. Q12 is turned on. but U3 UCC28180D is still working.. 

    therefore I think the problem occurs probably.. 

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Seongwoong,

    Thank you for your interest in the TIDA-01494 reference design.

    I'll try to answer your questions about this design, but I need to confer with the designer of it about these issues.
    Please allow some days for a reply.

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    ok. I look forward to it.. 

    In addition to the test result 

    At the moment that U2(UCC25630-D) is not broken. but U3 UCC28180D is broken. 

    so If replaced by a new chip then it's alive.. 

    I think that the important thing is that PFC is off  immediately whenever ac is off..

    but the state which  PFC is on takes 3 seconds.

    and At that time, if ac power is on, Q1, U3,U10, U1 is broken. 

    If replaced by new one, it is fine.. 

  • 0 in reply to Seongwoong kim
    Intellectual 480 points

    Out of curiosity, 

    The HV Pin of UCC25630-3 is connected to the GND in the datasheet,

    but the HV Pin of TIDA-01494 is connected to the 220 ac line.. 

    Is there a problem ? 

    Regards,

    English name : Nick

    Original name : Seongwoong Kim

     

  • 0 in reply to Seongwoong kim
    Intellectual 480 points

    One experiment. 

    If ac power is on without r34 (21.5k), the same problem happened.

    At the moment, The freq is 2kHz and duty is almost 95.. 

    The problem happens by the duty ratio.. ? 

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Nick,

    I have managed to contact the designer of this TIDA design.

    He informed me that he will look into your issues and questions.

    Can you please clarify this: you mentioned that the "the freq is 2kHz and duty is almost 95..":
    What frequency are you talking about? The PFC switching frequency? LLC? other frequency?

    Thank you,

    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hi Ulrich,

    it's PFW switching frequency. the measured freq is 2khz without r34(21.5k)...

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    Intellectual 480 points

    Hi Ulrich,

    How about that  without PFC Off functions ? 

    Is it fine under the conditions...?

    Q12, Q16 is not connected. and if ac power is turned on and off, is there no problem? 

    Would you please check as soon as possible. 

    If possible from your answer, I'll do the test..  

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello NIck,

    I have some answers and some questions for you.  First the answers:

    R27 is not connected (depopulated) to disconnect the FREQ pin of the UCC28180 from a Frequency-Dithering circuit made from U1A. U1A, R4, R5, R15, R23, and C24 comprise an oscillator that was temporarily used on the TIDA design for a test of EMI-dithering of the PFC switching frequency. The board designer decided not to use the circuit and removed R27 to disconnect it from U3.
    TIDA-01494 is okay to run without R27; no problem.

    R25 is part of an adjustment for the Burst Mode threshold of the LLC controller U2. The TIDA designer decided to set the Burst Mode threshold to the lowest possible level, and so depopulated R25.
    TIDA-01494 is okay to run without R25; no problem.

    Concerning the HV connection: At the time of the TIDA-01494 design, the UCC256303 was not yet released and parts were not available. So the designer had to use UCC256301 temporarily and this part requires HV to connect to the AC line. When the UCC256303 was finally released and available, he changed the LLC controller to UCC256303, but left the HV connection circuit in place. The HV pin on the UCC256303 has no circuit inside the device, so the external circuit does nothing.
    TIDA-01494 is okay to run with external HV circuit connected to UCC256303 HV pin; no problem.
    But to be consistent with the UCC256303 datasheet, I recommend to remove R10, R22, and R31 and connect the HV pin to PGND.

    R34 sets the switching frequency of the PFC controller U3 (UCC28180) and this resistor must be in place to operate correctly. Please do not remove R34. Your boost inductor is not designed to handle the very low open-circuit frequency of ~2kHz, and the inductor will saturate. This saturation may overstress Q1 before the ISENSE can detect the peak current and shut it off. Damage to Q1 can propagate through the gate drive to damage U3 as well. Damage to U3 can propagate from the VCC pin into AUX_15V and damage U10 and then U1.
    Please do not remove R34.

    Q12 and Q16 should remain in place. Please do not remove them.

    Now for my questions:

    1. There is a failure when you quickly turn off AC, and then turn on AC again. Is that correct?

    2. Initially you get 24V output, and then you turn-off the AC and then you turn-on the AC again, and you get a failure. Is that correct?

    Please verify if this is the correct sequence of your failure mode. If it is not the correct sequence, please clarify step-by-step so that I can follow from the point of first power-up to the point of failure.

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hi Ulrich,

    1. There is a failure when you quickly turn off AC, and then turn on AC again. Is that correct?

        - Yes. it's the same result that AC power is turned on without R34.

    1. Initially you get 24V output, and then you turn-off the AC and then you turn-on the AC again, and you get a failure. Is that correct

    - Yes. If ac power is turned off and on at the moment that aux_15V is alive, the problem occurred. 

    but If aux_15V power is off and ac power is on, there is no problem. 

    Thanks

    Regards,

    Nick. 

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hi Ulrich

    1. There is a failure when you quickly turn off AC, and then turn on AC again. Is that correct?

    • Yes, the problem occurred under the conditions that aux_15 power is alive.
    • Sequence 

    <No Problem>

    1. AC power is on then output power 24V, aux_15V is confirmed
    2. AC power is off then aux_15V is off
    3. AC Power is on , there is no problem. 

    <a problem>

    1. AC power is on then output power 24V, aux_15V is confirmed
    2. AC power is off then aux_15V is alive
    3. AC Power is on, there is  the same problem occurred without  R34

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Nick,

    Just to let you know, this matter has not been dropped.

    I am waiting to hear back from the TIDA designer. I have sent a reminder and hope to have an answer for you soon.

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hi Ulrich,

    ok. I've been looking forward to it.. 

    Thanks.

    I'm struggling to find out the problem and solution. 

    One experiment. 

    If using the fuse 3A(current), Only Q15 TK16G60W and Q1 TK31N60X and Fuse 3A are broken. 

    I think the problem is a turing on/off timing of AC Power.. 

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Nick,

    The designer's reply is a suggestion to reduce the value of the AC_IN filter cap C43 from 0.1uF down to 0.047uF. 
    Basically, this cuts the AC sensing time constant in half and speeds up the PFC_OFF timing.

    Please try this suggestion, and possibly lower values if 0.47uF is not low enough to completely solve the problem.

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hi Ulrich,

    I've already tested that point. but it'not working 

    PFC_Off time can be not reduced.. 

    but I'll try again.

    Would let us know another solution. ? 

    Thanks

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    Intellectual 480 points

    The below waveform is measured by the gate pin of UCC28180D after ac power off 

    c34 is changed by  47pF

    It seems that the power is a little bit alive.  

     

    There is no inrush in the TIDA-00779.. 

    Is the inrush part necessary ?

    How about applying to the TIDA-00779 Shutdown circuit ?

     

    Regards,

    Nick. 

     

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Nick,

    I am still waiting for the TIDA-01494 to provide another solution.  From your waveform, it looks like the PFC is enabled every other half-line cycle.  It could be that something on your board is only half-wave rectified, not full-wave.  Please check.

    Meanwhile the alternative PFC_ON circuit of TIDA-00779 (or an adaptation of it) can also work.  This TIDA does have an inrush limiter: R2 (after the Fuse F1 and RV1), and it is shorted out by relay K1 after the power-up inrush is complete, to reduce power loss.  
    I think this PFC on/off method may be more reliable than that in TIDA-01494.

    Regards,

    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hello Ulrich,

    I know that two N and L line of AC power needs to be off. 

    If N line - off and L line - On, ac power flows to the board.. it seems that it's half wave rectified.. 

    PFC on/off method TIDA-00779  is automatical or manual if AC is on? 

    I think that there is the S1 switch so PFC would be turned on manually?

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Nick,

    Yes, in the TIDA-00779 design, switch S1 is a manual on/off control for the PFC.

    But TIDA-00779 is a reference design; it is no intended to be a real product. It is rare that a reference design will meet a customer's real product specifications exactly in all detail. It is to be used as a reference for designing a real product, showing the major topological arrangement and component values relative to design target of the TIDA.  Customer specs may be similar or close to or far from the TIDA design, but major elements of the TIDA can be directly used or scaled to the customer requirements.

    In this case, a manual on/off is probably not feasible for a real product, and the switch will need to be replaced by some circuit that detects conditions for PFC on and off and drives the existing network appropriately.

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hello Ulrich,

    I keep testing without TK31N60X,S1F because the chip is broken frequently..

    whenever AC power on/off without TK31N60X,S1F, 

    TLV70433DBVR and TLV3202AID chip are broken.. 

    Why does it happen.. ?

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    Intellectual 480 points

    Hello Ulrich,

    PFC on/off method of TIDA-00779 would be better.. I found out the development direction.. 

    We will apply to it.. 

    Questions.

    after 27V/20A is loaded, the power is off for a few second.. 

    If 480W(24V/20A) is over, the module is shut down.. ?

    let me know how to increase power a little ? 

    Our reference is for 27V/20A.

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Nick,

    The TIDA-01494 is designed for 480W.  Your application apparently needs 27V x 20A = 540W, which is 12.5% higher output power.

    Since the output currents are the same, it shouldn't trigger the output current sense.  I think you may be hitting a power limit on the primary side.
    Please check the resistor value at ISNS on the UCC256303 (R3).  You may have to decrease it by 10~12% to allow a higher peak current.

    Another possibility is an over-voltage protection at the BW input. Please check values for R17 and R12, which are set for 24V at the output.
    Determine if they need to be revised for a 27-V output.

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hi Ulrich,

    L1 : 420uH 

    What is the current rate?

    PartNumber is 744355147 at the altium schematics ?

    The value is 470 nH/30A

    Which one is the right value?

    Would you let us know the ref value 420uH/18A or 20A?

    Regards,

    Nick. 

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Nick,

    In the BOM list for TIDA-01494, L1 is shown as:

    Being a PFC boost inductor, it makes sense that its value would be 420uH rather than 420nH.  The Wurth Electronics description indicates that it is rated for 56A, although this is considerable over-design for a 480-W system, even for 720W peak.  

    I was unable to find its datasheet.  Maybe you can request it from Wurth, however, it may be better to design or procure a smaller replacement that is more suited to your power level.  

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Intellectual 480 points

    Hi Ulrich,

    From design guide TIDA-01494, the calculated maximum current rate is 11A.. 

    so 11A is enough ? 

    it can not make them due to the size. if 56A, the line width is very high.. 

    Would you check from TIDA-01494 designer and engineer ?

    Regards,

    nick. 

  • 0 in reply to Seongwoong kim
    TI__Mastermind 40580 points

    Hello Nick,

     

    You are right to be concerned, because 11A peak current rating for the boost inductor is not enough.

     

    While reviewing section 2.3.1.3 of the TIDA-01494 Design Guide document, I see that equation (6) results in the 11.3A peak current in the inductor. This number is incorrect, and I came across a few other typographical errors in this section.  I don’t know how the errors came about.

     

    In any case, equation (6) calculates the peak current in the boost inductor, used to design it so that saturation may be avoided.

     

    For this design, IL(max) = (1.414 x 750Wmax/85Vrms/0.97) x (1 + 0.25/2) = 14.47Apk.
    This value has an estimated 0.97 efficiency factor included (not in the original equation). It is rather conservative for the peak current because the current ripple is not maximum at the peak of 85Vrms.

     

    I suggest to design the inductor to not saturate at a peak current of ~20A to allow for possible operation at input voltages < 85Vrms.
    Note: The 750W PFC power (for 720W LLC output power) is intended for only about 3 seconds of operation, so thermal design of this (and other components) does not need to accommodate 750W continuously. But the peak current may approach ~20A pk under certain limited conditions and it would be better not to saturate.

     

    Regards,
    Ulrich