How to Make a Simple Boost Converter with 555 Timer?

We may come across many circumstances where we need 12V from a 5V (as from USB ports which only provide 5V), but it may not be sufficient to drive all the circuits. To face such situations we are introducing a dc to dc boost converter circuit which can generate 12 volt from 5 volt. Today boost converter applications are used in different devices like dc dc power supply, dc-dc converter module, isolated dc dc converter etc. The main component used for this circuit is a 555 timer IC operating in astable mode. It generates a square pulse which is then given to a simple transistor inverter to get inverted outputs. These two outputs will drive a voltage pump which increases the voltage level by series addition. However this 555 timer boost converter has a disadvantage of low output current so it can’t drive high current devices. To get more current you have to use a step up converter circuit that we will introduce later.

Boost converter circuit schematic

boost converter circuit


  1. IC 555 
  2. Transistor (BC548) 
  3. Diode (IN4148-3Nos) 
  4. Resister (1K-2Nos, 10K-2Nos, ) 
  5. Capacitor (0.01uF, 0.1uF,10uF-2Nos,100uF)

How do dc to dc converters work?

  • 555 timer IC works in astable multi vibrator mode which produce a pulse of particular frequency, determined by the value of timing resistors and capacitors.
  • The output of this 555 is given to a transistor inverter which generates an inverted output. 
  • These outputs are then given to the voltage pump which increases the voltage level. 
  • Voltage pump produces high voltage by the series addition property of voltage. 
  • First capacitor charges in the positive cycle of square wave, this voltage charges the next capacitor. In the negative cycle voltage is added due to series addition.
  • This voltage is then stored in the 100uF capacitor. So finally we will get 12 volts at the output.

Components Pinout

So that's about it. Don't hesitate to comment for any uncleared doubts. Cheers!

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