Boost Converter Calculator (Non-Isolated)

This calculator will help you to design and find the optimal inductor value for a non-isolated boost (step-up) converter circuit, ensuring that your circuit works with an efficient operation with a 30% ripple current.

How to Use the Boost Converter Inductor Calculator

Steps to Use:

Enter the Input Voltage (Vin) = The voltage from your power source which you want to boost (e.g lets say 12V).
Enter the Output Voltage (Vout) = The desired boosted voltage value which you want at the output (e.g let us say 220V).
Enter the Switching Frequency (kHz) = The PWM switching frequency of your astable multivibrator circuit (e.g you can set it up to work with 50 kHz).
Enter the Output Current (A) = The expected load current, which you want to supply the connected load at the output (e.g 1A).
Click the "Calculate" Button = The results will then show up in the relevant fields:

• Duty Cycle (%) = How long the switch stays ON in one cycle.
• Optimal Inductor Value (µH) = The required inductor size for stable operation.

Example Calculation

Given:

• Vin = 12 V
• Vout = 220 V
• f = 50 kHz = 50,000 Hz
• Iout = 1 A

Step 1: Duty Cycle (D)

Formula:

D = 1 − (Vin / Vout)

Substituting:

D = 1 − (12 / 220)
  = 1 − 0.054545
  = 0.945455

Therefore....

D = 94.55%

Step 2: Estimated Input Current (Iin)

Formula:

Iin = Iout / (1 − D)

Substituting:

Iin = 1 / (1 − 0.945455)
     = 1 / 0.054545
     = 18.33 A

Therefore,

Iin ≈ 18.33 A

Step 3: Ripple Current (ΔIL)

If "Input Current (Recommended)" is selected:

ΔIL = 0.3 × Iin
     = 0.3 × 18.33
     = 5.50 A

Step 4: Inductor Value

Formula:

L = (Vin × D) / (ΔIL × f)

Substituting:

L = (12 × 0.945455) / (5.50 × 50,000)
  = 11.345 / 275,000
  = 0.00004125 H

Therefore,

L = 41.25 µH

Final Results (Using Ripple Based on Iin)

• Duty Cycle: 94.55%
• Estimated Input Current: 18.33 A
• Ripple Current: 5.50 A
• Optimal Inductor: 41.25 µH

As you can see, the duty cycle is so high at 95% which is a bad thing, so boosting voltage with this circuit from 12V to 220V looks like a bad idea.

So better to go with flyback SMPS topology instead.