Enable power using LTC4291 -1

Hi,

I am using LTC4291-1 & LTC4292 based design. Earlier i was using LTC4291 and i was using LTC4291 GUI application but since LTC4291 needed programming after each power on reset, i went with LTC4291IUF-1#PBF which is pre-programmed. I want to know how do i test? Do i need to use the same LTC4291 application or separate application is available for LTC4291-1?  if i try to use the same LTC4291 GUI application then it will load the application again. I am little confused how to proceed.

  • 0
    •  Analog Employees 
    on Apr 12, 2019 6:11 PM

    LTC4291-1 / LTC4292 can run autonomously by tying the AUTO pin high. With AUTO pin high during startup or reset, the PSE will operate in Auto mode. Each port will detect and classify repeatedly until a valid PD is discovered. LTC4291-1 / LTC4292 will then set ICUT-2P, ILIM-2P, and PCUT-4P according to the PSE assigned Class, apply power to valid PDs, and remove power when a PD is disconnected. Maximum Delivered power in Auto mode can be set by the PWRMD1 and PWRDMD2 pins.

    You can use the same LTC4291 QuikEval GUI with LTC4291-1. First, make sure the AUTO pin is low at startup. Then open the software, same as before. After scanning for PSEs, you can skip the code download option as the LTC4291-1 already has the latest firmware. You can then initialize the PSE or jump straight to the main GUI.

    Best Regards,

    Eric

  • Hi EHorsma,
    Thanks for your suggestion. I did try setting AUTO pin high and this enabled power without need to program.

    I have question on though. 2 ports out of 4 are not supplying power. I have checked MOSFET gate pulse switching. There is no any switching on these 2 gates. other 2 gates are high and hence output power is supplied. I want to know in what case 2 ports can supply power but 2 fails to do so in the same chip. what may be wrong in two ports not supplying power?

  • 0
    •  Analog Employees 
    on Apr 20, 2019 1:29 AM in reply to Narendrasingh

    Please provide more information.  There are multiple reasons why a port may not power.  The PSE may not be properly configured (HW or SW).  The PD may not provide the correct detection/classification signature and the port never powers.  There could be a fault after power on causing port power to be turned off and appearing as if the port is not powered.

    1) Is the PSE performing detection and classification?  The QuikEval GUI will provide information on the detect and class results.  You may also probe the channels of the port to see if there is a detect signal.  The datasheet shows some single signature and dual signature detect/class/power on waveforms.

    2) Which 2 ports are working?  Is it always the same 2 ports?  Or is it when 2 ports are on, 2 will not work?

    3) What PD is connected?  When moving the same PD from one port to another still powered?

    4) Is the PD is powering on and off?

  • Hi dreyeslt,

    Sorry for late reply as i was unavailable.

    Now, I am able to get output on the 2 non-working ports also. I am not sure of the cause for the misbehavior although i had tried multiple times and all times it was unable to deliver power earlier.

    I have another board in which i am getting similar problem. All the 4 ports are not delivering power.

    1) Is the PSE performing detection and classification?  The QuikEval GUI will provide information on the detect and class results.  You may also probe the channels of the port to see if there is a detect signal.  The datasheet shows some single signature and dual signature detect/class/power on waveforms.

    When i check waveform, the PSE is failing to detect and classify and hence trying to detect again and again. I have attached snap for your reference.

    2) Which 2 ports are working?  Is it always the same 2 ports?  Or is it when 2 ports are on, 2 will not work?

    yes, the particular 2 ports were not enabling power. others 2 were enabling all the times.

    3) What PD is connected?

    I am using based PD.

    4) Is the PD is powering on and off?

    yes PD gets powered ON and OFF in my working PSE but fails in non-working.

    NON- working board detection snap

    Waveform of OUT to AGND pin in non-working board with design based PD

    Waveform of OUT to AGND pin in working board with the same PD

  • 0
    •  Analog Employees 
    on May 21, 2019 4:47 PM in reply to Narendrasingh

    How much capacitance is there at the port output?  Are there additional components at the port output other than what is shown on the demo board?