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TLV61048: Short circuit when power on

Alberto Cutone
Prodigy 20 points
Part Number: TLV61048
Other Parts Discussed in Thread: TPS61372

Hello,

I've a problem in my project in which I'm using a TLV61048 to boost my voltage from Vbat(3V7) up to 5V or 12V, depending on the S6 switch position. 

My board without the TLV61048 works correctly, but if I switch it on ( using the enable pin ) I have a short circuit, and the TLV61048 blows up.

Removing it, the circuit restarts to work correctly ( of course a part the booster voltage feature ). 

What I'm doing wrong?Please find attached the schematic (see the 5V5 regulator section) and the layout.

Many thanks for the help.

  • 0
    TI__Mastermind 21565 points

    Hi Alberto:

    May I know how many boards you test? And what's your load condition?

    Then please replace a new IC and measure the waveform of EN, Vin, SW, Vout during the startup. 

  • 0 in reply to Minqiu Xie
    Prodigy 20 points

    Hi Minqiu,

    thank for you reply. I've tested it on several boards.

    I had a MCP1703 voltage regulator as load ( from 5.5 to 5V ).

    Removing the regulator the TLV61048 works, but when the enable is off I still have an output of about 3.7V (it should be 0)

    I have noticed that the device is very close to the battery connector, can it be related ?

    How can I have 0V when the enable is off?

    Many thanks,

     Alberto

  • 0 in reply to Alberto Cutone
    TI__Mastermind 21565 points

    HI Alberto:

    If the TLV61048 works after removing the load, I will suspect it's related to the load. You could use a resistance or E-load to simulate the load and test TLV62048 performance at first. And check the circuit of MCP1703 in the same time.

    For your question about disable the TLV61048, you can find there is a inductance and diode connecting the input and output. So Vout will be Vin-Vdiode if disable the boost converter.

    If you need to disconnect input and output, we will recommend to choose alternative parts, such as TPS61372.