Learn how to build an efficient boost converter to provide high voltage from a lower voltage greater than 5V for several applications, most prominently to charge capacitors. The boost converter described here utilizes the Astable operation of the NE555 a timer Integrated Circuit, an IGBT, a Diode, and an Inductor coil of wire.
RA, RB, and CA control the frequency and duty cycle of the output of the NE555 chip. In order to determine the values for RA, RB, and CA( See Schematic) you must determine your desired input and output voltage. After you determine your input (Vi) and output (Vo) voltage you can plug it into this equation to determine the duty cycle( D) required by the NE555.
D=1-( Vi / Vo)
you can use the link below to calculate the values of RA, RB, and CA. I recommend using a -frequency of 20-30kHz for your calculation. NE555 Calculator
Although the duty cycle calculation is, or should be, a close representation of the input/output relationship it is important to experiment with a breadboard with different values for your capacitor (CA) and variable resistors (Potentiometers) for RA and RB in order to get your circuit perfect before permanent installation. When experimenting with a bread board use half of your desired final input voltage just in case an unexpected voltage kills the IGBT, I’ve fried several. Also monitor your IGBT’s temperature and install a heat sink to keep it from over heating during testing, note once an appropriate inductor is used your IGBT will only warm up.
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