5V to 12V Step Up DC-DC Converter

  • Rajkumar Sharma
  • 82108
  • easy
  • Tested


Step up DC-DC converter is based on LM2577-ADJ IC, this project provides 12V output using 5V input, maximum output load 800mA. The LM2577 are monolithic integrated circuits that provide all of the power and control functions for step-up (boost), fly back, and forward converter switching regulators. The device is available in three different output voltage versions: 12V, 15V, and adjustable.

Requiring a minimum number of external components, these regulators are cost effective, and simple to use. Listed in this data sheet are a family of standard inductors and fly back transformers designed to work with these switching regulators. Included on the chip is a 3.0A NPN switch and its associated protection circuitry, consisting of current and thermal limiting, and under voltage lockout. Other features include a 52 kHz fixed-frequency oscillator that requires no external components, a soft start mode to reduce in-rush current during start-up, and current mode control for improved rejection of input voltage and output load transients.


  • Requires Few External Components
  • Input 5V DC
  • Output 12V DC
  • Output Load 800mA
  • Current-mode Operation for Improved Transient Response, Line Regulation, and Current Limit
  • 52 kHz Internal Oscillator
  • Soft-start Function Reduces In-rush Current During Start-up
  • Output Switch Protected by Current Limit, Under-voltage Lockout, and Thermal Shutdown
  • PCB Dimensions: 45.72 x 34.29 mm

Project is based on LM2577-ADJ IC for flexibility to obtain other output voltages by changing value of feedback resistors R2 and R3

Output Voltage Formula V Out=1.23V (1+R2/R3) (Read Data Sheet for more information about Inductor value, Capacitor, Feedback resistors, Output current and voltage)



How It Works

LM2577 turns its output on and off at a frequency of 52 KHz, and this creates energy in the inductor L1.

When the NPN switch turns on, the inductor current charges up at a rate of vin/L1, storing current in the inductor. When the switch turns off,, the lower end of the inductor flies above Vin, discharging its current through diode into the output capacitor at rate of (Vout-Vin)/L1. Thus energy stored in the

inductor during the switch on time is transferred to the output during the switch off time. The output voltage is controlled by amount of energy transferred which , in turn, is controlled by modulating the peak inductor current. This is done by feeding back portion of the output voltage to the error amp, which amplifies the difference between the feedback voltage and a 1.23V reference. The error amp output voltage is compared to a voltage proportional to the switch current ( ie., inductor current during the switch on time)

The comparator terminates the switch on time when the two voltages are equal, thereby controlling the peak switch current to maintain a constant output voltage.

Parts List



LM2577 Datasheet




  • mukesh

    how go buy this item

    3 years ago
  • Jeffrey Fernandez

    is it really working sir? i badly needed one. Thanks 🙂

    3 years ago
    • admin

      This is a tested project. Thanks

      3 years ago
  • What will be the PCB dimensions and diode 1N5822 is not available will Diode 1N5819 will do? Plus SMD Capacitor 330nf 1206 is this ok?

    2 years ago
    • admin

      Try to print the PCB from the PDF file and it will be in correct dimensions. The diode used in this project is rated at 3A but the diode you mention is rated at 1A so there is possibility of damaging the diode on full output. Capacitor C4 should work fine.

      2 years ago
  • raihan

    sir can you kindly show the pictures of LM2577ADJ

    2 years ago
  • asif ali nawaz

    why am I getting same voltage at output which I’m applying at input.

    1 year ago
    • admin

      This means that the IC isn’t oscillating. Please check for damaged parts and shorts.

      1 year ago
  • naman jain

    Sir how to convert 5v in variable voltages using R1 and R2

    1 year ago
    • admin

      I would suggest to read the LM2577-ADJ datasheet on how to change the output voltage. Output voltage is controlled using R2/R3 resistors of the schematic above.

      1 year ago
  • Sumit

    Can i use for 12 volt 10 watt led light to 5 volt power input ???

    10 months ago
    • If you LED draws less than 800mA then you can safely use this 5V to 12V converter to power the LED.

      10 months ago
  • Roope

    Im just asking what voltage size should C3 and C4 be?

    7 months ago
    • C3 should be at least 16V and C4 10V

      7 months ago
  • WWWL

    Dear, where can i find the dimensions of the printboard?

    6 months ago
    • Raj

      Hi, Dimension for this PCB 45.72X34.29MM

      6 months ago
    • I’ve updated the project with PCB dimensions.

      6 months ago
  • Antonio JosĂ© Montaña

    SALUDOS DESDE VENEZUELA HERMANO…!!! Una pregunta tienes por casualidad elaborado un proyecto, o pudieras realizarlo, para covertir el voltaje de dos pilas AAA(1,5 Volt. C/U) a 9 Volt. Se trata de poner a funcionar un MicrĂłfono inalámbrico que usa baterĂ­a de 9 Volt con las dos baterĂ­as AAA, ya que en nuestro paĂ­s esta baterĂ­a de 9 Volt es muy dificil de conseguir y al conseguirla es muy costosa…!!! Gracias por su respuesta amigo. DIOS TE BENDIGA Y TE CUIDE CON TU BELLA FAMILIA…!!!

    6 months ago
    • Could you post in English, please?

      6 months ago
  • m.a.sadeghi

    i wanna use it for laptop cooler fan can it damage the laptop ?

    3 months ago

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