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TPS54232: Design is not working below 4.8V input.want to implement design with input voltage range from 4V to 24V with output of 3.3V @ 2A.

Chand Padaliya
Prodigy 60 points
Part Number: TPS54232
Other Parts Discussed in Thread: TPS54202

To TI Support Team,

as per TPS54232 datasheet device should work between input of 3.5V-28V.

I have implemented design using TPS54232 which should run on input range from 4V to 24V.

But at the input of 4V i am not able to get output of 3.3V @ 2A.

output is varying between 2.56 to 2.75V.

as per requirement design should work on 4V & 24V DC input.

is there any TPS54232 device constraint?

why i am facing this type of issue.

Please suggest.

Thanks,

  • 0
    TI__Expert 7500 points

    Hi,

    From the datasheet, Figure 12 shows the maximum output V.S. input voltage at 2A. From the picture, TPS54232 may can't support 4Vin-3.3Vout at 2A loading.

    And I will also double check with the correct apps engineer and get back to you ASAP.

    Thanks,

    Lishuang

  • Former Member
    0 Former Member

    Hi Padaliya,

    TPS54232 is a non-synchronous buck converter, and the high-side MOSFET is N-channel MOSFET.

    To drive this HS MOSFET properly, a bootstrap circuit is designed to generate a floating power supply between gate node and source node of the MOSFET and an external small ceramic capacitor between the BOOT and PH pins is required. This bootstrap capacitor is refreshed when the HS MOSFET is off and the catch diode or low-side (LS) MOSFET conducts. An undervoltage lock-out (UVLO) circuit is also required for the gate drive supply to keep the converter from attempting to switch when the gate drive may be too low(BOOT-PH<2.1V).

    It means that in non-synchronous buck converter (TPS54232) when the targeted Vout is close to Vin, the BOOT-PH (gate drive) voltage is lower than 2.1V, then HS and LS MOSFET will be turned off, leading unstable and not correct output.

    There are several solutions for the low drop-out operation. Please check the app notes for detailed explanation :

    Thanks.

    Bruce

  • 0 in reply to Former Member
    Prodigy 60 points

    Thanks Bruce for Reply,

    As per your inputs Design will work between 3.5-8V only?

    i need to implement circuit will run on minimum input voltage of 4V and max 24V with output of 3.3V @ 2A.

    Thanks & Regards,

    Kindly Suggest.

  • Former Member
    0 Former Member in reply to Chand Padaliya

    Hi Chand,

    The solution2+A can work between 4V-28V.(Diode tied from output to BOOT + Dummy load)

    And according to the test results, at least 4-mA dummy load should be added to ensure the device can start-up at 4Vin and no loading condition.

    By the way, could you please share me your application and why 4Vin is needed? If 4.5V input can be accepted, TPS54202 can directly be used with no additional design.

    Thanks.