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TPS65130: Issue of startup current

user3895136
Prodigy 10 points
Part Number: TPS65130

There is a issue with the startup current of the TPS65130.

The circuit needs to be able to generate + 12V and -12V from + 5V DC. And there are severe restrictions on the input current. (under 350mA)

What is the way to reduce the startup current? Or what other devices have lower startup current?


The problems that are occurring are as follows.

The current at startup is about 1A at maximum. (Too much current)
Because of higher startup current, input voltage (+5V) drop down.
As a constrain, input voltage must not drop down. So I'm looking for way to reduce startup current.

conditions:
Output power supply About 30mA for each rail
Controls ENP / ENN. Both positive and negative are valid

WAveform Description
channel 1 : ENN/ENP
channel 2 : +5V input
channel 3 : +12V Output
channel 4 : input current

  • 0
    TI__Mastermind 18550 points

    Hello,

    Thank you for your post. We will look into it in detail and provide any feedback to you by Monday, 2/24/20.

    Kind Regards,

    Liaqat

  • 0
    TI__Mastermind 18550 points

    Hello,

    Startup current is high when positive and negative supplies first ramp up because output capacitor are being charged. One way to reduce the start up current is to not enable the positive and negative outputs at the same time so that they ramp at different times and hence charging only the respective capacitance. ENP and ENN are the enable controls for positive and negative supply respectively that can be used to achieve that. Reducing the output capacitance may also reduce initial charge current but that should be done carefully as it can impact stability of the converters.

    Kind Regards,

    Liaqat