Modern processors operate at extremely low voltages while consuming large amounts of current.

A server CPU, GPU, FPGA, or AI accelerator may require:

• 1.0V output
• 50A to 300A load current

These applications require carefully optimized inductors capable of handling high current while maintaining efficiency and thermal performance.

In this example, we will walk through the design process for a single-phase regulator supplying 1V at 50A from a 12V input source.

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Design Requirements

Assume:

Input Voltage:

12V

Output Voltage:

1V

Output Current:

50A

Switching Frequency:

500 kHz

Ripple Current Target:

20%

Maximum Temperature Rise:

40°C

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Why This Design Is Challenging

Compared to many power supplies:

• Current is very high
• Output voltage is very low
• Efficiency is critical
• Space is limited

Even small losses become significant.

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Step 1: Determine Ripple Current

Ripple current target:

20%

Therefore:

50A × 20%

= 10A ripple

Ripple current affects:

• Peak current
• RMS current
• Copper losses
• Saturation margin

👉 Related Guide: Ripple Current Explained

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Step 2: Calculate Duty Cycle

For a buck converter:

Duty Cycle:

1V / 12V

≈ 8.3%

The converter spends most of its time in the OFF state.

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Step 3: Estimate Required Inductance

A practical design may target:

0.15 µH to 0.5 µH

For this example:

0.22 µH

This provides acceptable ripple current while maintaining transient response.

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Step 4: Calculate Peak Current

Peak current becomes:

50A + (10A ÷ 2)

= 55A

This value must remain below the saturation limit.

👉 Related Guide: Understanding Magnetic Saturation

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Step 5: Energy Storage

Although inductance is small, current is large.

Energy storage remains important.

The stored energy is:

E = ½LI²

Despite the small inductance value, high current creates significant magnetic energy.

👉 Related Guide: How to Calculate Inductor Energy Storage

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Step 6: Core Selection

Candidate materials include:

• Ferrite
• Powdered Iron
• Nanocrystalline

For this example:

Ferrite is selected because:

• Excellent high-frequency performance
• Low losses at 500 kHz
• Compact size

👉 Related Guide: How to Choose the Right Core Material

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Step 7: Current Density Considerations

At 50A, conductor selection becomes critical.

Possible solutions include:

• Heavy copper windings
• Parallel conductors
• Copper foil
• PCB-integrated inductors

Current density strongly affects temperature rise.

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Step 8: DCR Optimization

In low-voltage regulators, DCR becomes extremely important.

Even:

0.5 mΩ

can generate meaningful losses at high current.

👉 Related Guide: What Is DCR in an Inductor?

Reducing DCR is often a primary optimization goal.

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Step 9: Thermal Evaluation

Heat sources include:

• Copper losses
• Core losses
• AC winding losses

👉 Related Guide: Inductor Temperature Rise Explained

Thermal management becomes one of the most important design constraints.

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Step 10: Multiphase Converters

In practice, many CPU regulators use:

• 4 phases
• 8 phases
• 12 phases
• 16 phases

This reduces:

• Ripple current
• Inductor size
• Thermal stress

Each phase uses its own inductor.

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Practical Design Tradeoffs

Engineers must balance:

• Inductance
• Current capability
• DCR
• Thermal performance
• Size
• Cost

Improving one parameter often affects another.

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What Automated Design Tools Can Do

Modern magnetic design tools can evaluate:

• Saturation margin
• Temperature rise
• DCR
• Core losses
• Manufacturability

allowing engineers to compare multiple solutions rapidly.

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Conclusion

High-current regulator inductors represent some of the most demanding magnetic components used in modern electronics.

By carefully balancing inductance, current handling capability, DCR, thermal performance, and saturation margin, engineers can create efficient and reliable power delivery systems for processors and advanced computing platforms.

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Need Help Designing High Current Inductors?

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