Where do I start when choosing a DC-DC converter?

Start with the rails, not the part: decide the input range, the output voltage and current, whether isolation is required, and the thermal environment. Those numbers narrow the choice quickly. Then confirm the package and the pinout.

When do I need isolation?

Use an isolated converter when the input and output grounds must be separated, to break ground loops, protect sensitive circuits from input transients, or meet a safety requirement. Where isolation is not needed, a non-isolated regulator is simpler.

Buck or boost: how do I choose?

A buck converter steps the voltage down and a boost converter steps it up, and the choice follows from the input and output voltages. Confirm the topology against the rail and the load.

What safety points matter for a mains supply?

Isolation, creepage and clearance are safety-critical, and the input protection and the fuse must be chosen for the application and the standard the product must meet. Our FAE team helps with the safety design during design-in.

How do I pass EMC with a switching supply?

Use the input filter the datasheet recommends, keep the switching loop small, and follow the reference layout. EMC is decided by the layout and the filter as much as by the supply. Measure the spectrum on the bench before production.

How do I manage the thermal design?

Size the supply for the peak load with margin for the derating at high temperature, and provide the cooling the datasheet requires. Validate the design in the real enclosure. A supply that is cool on the bench can overheat inside a sealed enclosure.

My converter fails EMC. Where do I start?

Start with the switching loop: a large loop radiates and couples noise. Keep the loop as small as possible, place the input capacitor close, and return the current directly beneath the trace. Then check the filter against the spectrum.

Why is my output ripple higher than the datasheet?

Excess ripple usually comes from the layout or the output capacitor: a long output loop, an inadequate capacitor, or a capacitor placed too far from the load. Measure the ripple at the load, not at the converter.

How do I measure EMC and ripple correctly?

Use the correct probe and bandwidth, measure at the point of interest, and keep the setup consistent between measurements. A wrong probe or a moved cable changes the result. Measure the conducted emissions with a LISN against the standard's limit.

What makes a supply medical-grade?

A medical supply provides reinforced isolation and low leakage current to meet the safety standard, along with the documentation to support the product's safety case. The requirements are stricter than for a general-purpose supply.

Why does output noise matter for precision equipment?

A sensitive analog or measurement load is affected by the noise on its rail, so a low-noise supply, or a post-regulator after a switching supply, preserves the accuracy of the measurement. Noise is as important as the output voltage.

How do I validate the supply for my application?

Measure the isolation, the leakage and the output noise with the real load and the real layout, and confirm the documentation supports your safety case. Our FAE team can measure the supply in our lab.

When do I need a Type B sensor?

Use a Type B sensor when a DC fault current can appear, such as in EV charging, because a sensor that only detects AC would miss it. Where no DC fault current can appear, an AC sensor is enough. The application and the standard decide the choice.

How do I set the detection threshold and the response time?

The threshold and the response time are set by the standard the product must meet, not by preference, so confirm the requirement and design to it. Validate the response time on the bench.

How do I integrate the sensor?

The sensor output feeds the controller, which compares it with the threshold and trips the contactor on a fault. Keep the sensor output away from switching circuits and validate the trip on the bench. Our FAE team helps with the integration.

Technical Support | Hawun Expertise | BeiLuo

Guides, application notes, troubleshooting and reviews from BeiLuo's FAE team, covering Hawun DC-DC and AC-DC converters, supplies and current sensors.

Guides 2 Application Notes 1 Troubleshooting 1 Reviews 1

How to Select a DC-DC Converter for Your Power Design

2026-10-08 - Guides - By Kevin Zhang

Compare isolated DC-DC converters by input range, output voltage, power, isolation and package to choose the right module for your industrial or telecom design.

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How to Select and Integrate a Residual Current Sensor

2026-08-30 - Guides - By Michael Chen

How to select a residual current sensor for EV charging and industrial protection, covering Type B detection, thresholds, response time and integration.

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AC-DC Power Supply Design and Safety Application Note

2026-09-30 - Application Notes - By Kevin Zhang

Practical guidance for designing the input protection, filter, isolation and thermal path of an AC-DC power supply so efficiency, EMC and safety meet specification.

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Troubleshooting EMC and Ripple in Power Converter Designs

2026-09-21 - Troubleshooting - By Michael Chen

A systematic procedure for diagnosing EMC, ripple and noise problems in converter and supply designs, with the layout, filter and measurement checks that find the cause.

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Hawun Medical and Precision Power Supplies: A Practical Review

2026-09-13 - Reviews - By Sophia Liang

A practical review of Hawun medical-grade and precision power supplies for sensitive equipment, covering isolation, leakage, output noise and integration.

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Meet Our FAE Team

Kevin Zhang

FAE Engineer, Power Conversion

DC-DC ConvertersAC-DC SuppliesIsolationThermal Design

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Michael Chen

FAE Engineer, EMC and Sensing

EMCLayoutCurrent SensorsProtection

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Sophia Liang

FAE Engineer, Medical and Precision

Medical SuppliesIsolationLow NoiseSafety

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