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TPS55288: Design review

JH Shin
Guru 11450 points
Part Number: TPS55288


Hello,

The customer tested the operation of the TPS55288RPMR designed with the following schematic.

They checked that the input 12V and EN 4.5V are normally input. But the output is 0V. DR1L and DR1H are also 0V and do not operate normally.

TPS55288RPMR(TI)_230525.pdf

Q1 ) Please review if there is a problem with the circuit design.

Q2 ) Please advise on the cause of the issue and how to solve it.

Thank you.

  • 0
    TI__Mastermind 28700 points

    Hi JH,

    What is the customer and their application here?

    What is the input voltage range, output voltage and max output current?

    This device is I2C version, without I2C, it can't operate. I see SCL, SDA and MODE pins are all open, the device can't work with these pins open.

    Regards,

    Bryce

  • 0 in reply to Bryce Xun
    Guru 11450 points

    Hi Bryce,

    Thanks for your reply.

    The customer's responses.

      1. Applicaiton : WiFi 6E CPE

      2. Input range : 3.7V ~ 12V

      3. Output range : 5V

      4. Max output current : 6A

    Q1) Doesn't TPS55288RPMR work as stand alone?

    Q2) Mode pin is open. Should a connection through a resistor be added?

    Q3) I2C is connected to the AP's I2C pin, so communication is possible. How can they control it in SW through I2C to operate?

    Thanks,

  • 0 in reply to JH Shin
    TI__Mastermind 28700 points

    Hi JH,

    Thanks for feedback, here are my comments.

    About the schematic:

    1. Will the device work in 3.7Vin, 5Vo/6A? If so, the inductor needs to change with a higher Isat one, because the inductor current would be around 5V*6A/0.95/3.7V=8.5A which is higher than 8A, the inductor would be saturated which could cause very high peak inductor current and device damage.

    2. SCL and SDA pins must be connected to MCU so device can work.

    3. MODE pin can be open, then I2C slave address is 75h and PFM mode is chosen. Also, you will need to connect external 5V supply to VCC. Or you can connect 0ohm resistor from MODE to GND.

    4. Recommend to change R411 to 1.5k, C424 to 10nF.

    5. Recommend to add 0.1uF close to Vout and PGND pins. Also, the layout of this 0.1uF cap is critical.  

    Q1) Doesn't TPS55288RPMR work as stand alone?

    -> No, it needs I2C communication, so MCU is required. You can use TPS552882 which is non-I2C version.

    Q2) Mode pin is open. Should a connection through a resistor be added?

    -> See above3.

    Q3) I2C is connected to the AP's I2C pin, so communication is possible. How can they control it in SW through I2C to operate?

    -> You can refer to below register maps. First, make sure I2C communication is successful. Then, you can change the register value, and write to OE bit to 1, output can be enabled.

    Regards,

    Bryce