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LM2623: can anyone provide circuit using lm2623 for output voltage 3.3v

AMIT MAID
Intellectual 300 points
Part Number: LM2623

i have done circuit for 3.3v supply using lm2623 but its not working properly, dose anybody have done it, please provide the circuit diagram.

 thanks in advance.

  • 0
    TI__Mastermind 34201 points
    HI Amit,

    What's the input and output voltage? If you don't mind please provide your schematic and layout for us to check for the failure reason.

    Regards,
    Zack
  • 0 in reply to Zack Liu
    Intellectual 300 points

    Hi zack thanks for the reply,below is the attached circuit, we wanted 3.3v at output for input range of 1-14v.

    but i am getting 3.3v at output for only 2.3-3.8v, but still my controller is not working in this condition.

     

  • 0 in reply to AMIT MAID
    TI__Mastermind 34201 points
    Hi Amit,

    What's the load current?
    The inductor L102 MLZ1608M4R7WT000 saturation current is too small. If the inductor is saturated, LM2623 may enter into current limit. Please check the inductor's saturation current.
    When there's a 2V input voltage, what does Vo look like?

    Regards,
    Zack
  • 0 in reply to Zack Liu
    Intellectual 300 points

    load current is 5-10mA,

    inductor's saturation current is 127mA which is exceeded for 2v supply. but for higher voltages current is 10-30mA. in the range 2.5 to 3.8v supply ic workes but above 3.8v input, ic dose not worke and  output at ic is same as input. is it possible to get same output of 3.3v for complete input voltage range?

    thanks for your support.

  • 0 in reply to AMIT MAID
    TI__Mastermind 34201 points
    Hi Amit,

    LM2623 is a boost converter. It means output voltage is higher than input voltage. When Vin is higher than regulation voltage 3.3V, the ic will work at bypass mode and the output voltage will be one diode drop voltage lower than input voltage.

    So, you want to get a 3.3V output voltage now. And your input voltage range is 1-14V. Right?
    You may need a sepic circuit. I'll try to find a circuit.

    Regards,
    Zack
  • 0 in reply to Zack Liu
    Intellectual 300 points
    hi zack thanks for your support, is it possible to change in the existing circuit.or you can give another circuit,

    controller i am using needs current in uA can it work on mA?

    thanks and regards

    amit
  • 0 in reply to AMIT MAID
    TI__Mastermind 34201 points
    Hi Amit,

    I think SEPIC conveter is a good choice for your application.
    Firstly, I want to know some detail information about your application before i choose the right IC. You said the input voltage is from 1-14V, it's too difficult to choose a device that can get 3.3V@10mA at this whole rang. We don't have too many device that can start working from Vin equals 1V. It's too low.
    If your application start up voltage is beyond 3.3V and then go back to lower voltage to like 1V-3V. We'll better solutions. Please tell me more information about it.

    Thanks.
    Zack.