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TPS2543: About Momentary Power off & Humming Noise

SUHAS SHESHACHALA
Prodigy 40 points
Part Number: TPS2543

Hello,

We are using TPS2543RTE in one of the product we are developing, We are using it in below configuration and we noticed a couple of things :

Configuration "Charging downstream port, BC 1.2, with load detection enabled" :

CTL1 = 1

CTL3 = 1

CTL3 = 1

ILIM_SEL = 1

1. When a nonintelligent USB Load [without D+ & D-] which draws 2A or the Mobile which draws 1.5A is connected, it starts charging, turns off for a moment and then starts charging again. Why does this type of behaviour occur? Is it normal?

2. When a low current device like mouse which draws 0.3A or fitness band which draws 0.07A is connected humming we can hear a high frequency humming why does this occur

  • 0
    TI__Mastermind 30000 points

    Hello,

    SUHAS SHESHACHALA said:
    turns off for a moment and then starts charging again.

    Would you be able to elaborate on what you mean by turns off? Does VBUS drop? Could you capture the DP/DM lines plus VBUS on an oscilloscope during this point in time

    For question 2, I suggest looking at the power supply that you have connected to the TPS2543. There are no switching components in the TPS2543 that would create such a noise so I recommend looking elsewhere in your system during this event

  • 0 in reply to Adam Mc Gaffin
    Prodigy 40 points

    Hello Adam,

    Thank you for your reply,

    w.r.t Humming Noise, I will have a deeper look at the power supply section.

    w.r.t Momentary Turn Off, Below is the link to the small video showing this behavior, Please have a look and hope you can make out something.

    photos.app.goo.gl/FerFimyZm7UvXWBVA

    [This behavior occurs every time even when the mobile is connected]

    Thanks & Regards

    SUHAS S

  • 0 in reply to SUHAS SHESHACHALA
    TI__Mastermind 30000 points

    What is your current limit resistor set to? An over current event could be tripping and shutting off the internal power path. 

    What are the CTL pins connected to? Changing between charging modes would cause for a VBUS discharge so make sure that the voltage on the CTL pins stable

  • 0 in reply to Adam Mc Gaffin
    Prodigy 40 points

    The issue has been resolved and below is the reason/solution

    1. w.r.t Humming issue                                                                                                                                                                                                                         

    It was observed that the humming noise issue which was present with low power loads on TPS2543 is due to low input voltage, The issue was resolved when the input voltage was increased.

    2. w.r.t Momentary Turn-Off issue                                                                                                                                                                                                         

    It is the behavioral trait of TPS2543, and below is the explanation mentioned in the datasheet of TPS2543 [SLVSBA6A –FEBRUARY 2012–REVISED OCTOBER 2016] in Page No. 26 - 8.4.1 DCP AUTO Mode.          "As mentioned above the TPS2543 integrates an auto-detect state machine that supports all the above DCP charging schemes. It starts in Divider1 scheme, however if a BC1.2 or YD/T 1591-2009 compliant device is attached, the TPS2543 responds by discharging OUT, turning back on the power switch and then moving to BC1.2 DCP mode. It then stays in that mode until the device releases the data line, in which case it goes back to Divider1 scheme. When a Divider1 compliant device is attached the TPS2543 will stay in Divider1 state. Also, the TPS2543 will automatically switch between the Divider1 and Divider2 schemes based on charging current drawn by the connected device. Initially the device will set the data lines to Divider1 scheme. If charging current of >750 mA is measured by the TPS2543, it discharges and then switches to Divider2 scheme and test to see if the peripheral device will still charge at a high current. If it does then it stays in Divider2 scheme otherwise it performs OUT discharge and will revert to Divider1 scheme."

    Thanks & Regards

    SUHAS S