Calculating Power Density in Miniature HV DC-DC Converters

The electronic components used in military and scientific applications must be precise, reliable, and efficient. Powering advanced systems must meet extreme standards where every millimeter of space and every watt of power matters. This focus on optimization brings the concept of power density to the forefront, a critical metric for evaluating the performance of high-voltage power supplies.

It’s valuable to understand the intricacies of power density and how to calculate it in miniature HV DC-DC converters. Learn about how DC-DC converters function, why power density matters, and the factors that affect achieving maximum power density. By mastering these principles, you can make informed decisions when selecting power solutions for demanding applications.

What Are HV DC-DC Converters?

High-voltage (HV) DC-DC converters are electronic circuits that take a direct current (DC) input voltage and produce a higher DC output voltage. Their primary function is to provide stable, regulated high-voltage power to components and systems that require it, all while operating from a low-voltage source.

Why They’re Essential

DC-DC converters are the unseen workhorses behind many advanced technologies. The common thread across the following applications is the need for high performance in constrained environments. As devices become smaller and more powerful, the ability of a converter to deliver significant power from a minimal volume becomes a defining feature.

• Military: Converters power radar systems, unmanned aerial vehicles (UAVs), and night vision goggles. The need for lightweight, compact, and reliable power sources makes them vital for field operations.

• Aerospace: In satellites, spacecraft, and avionics, HV DC-DC converters drive critical systems like traveling-wave tubes (TWTs) for communications and electrostatic thrusters for propulsion. Every gram of mass saved translates to lower launch costs and increased payload capacity.

• Scientific: Precision instruments, including mass spectrometers, electron microscopes, and DNA sequencing equipment, rely on the stable and clean high voltage outputs provided by these converters. Their small footprint allows for the development of more compact and portable laboratory and diagnostic tools.

What Is Power Density?

Power density is a measure of a power converter’s output power relative to its physical volume. It’s expressed in watts per cubic inch (W/in³) or watts per cubic centimeter (W/cm³). In simple terms, power density answers this question: How much power can fit into a given amount of space?

A high power density indicates an efficient and well-engineered design. It allows for the creation of small, lightweight products without diminishing power output.

However, power density is not just about size. It’s intrinsically linked to efficiency and thermal performance. A converter that generates excessive heat will have a lower effective power density, as it may require additional space for heatsinks or other cooling mechanisms. Therefore, achieving high power density is a balancing act between power output, physical volume, and thermal management.

Key Factors Influencing Power Density

Input Voltage and Output Power

The relationship between input voltage, output power, and current directly impacts the design and, consequently, the power density. Generally, for a given power level, operating at a higher input voltage allows for lower input current.

Lower current reduces the dissipation of electrical energy in traces and inductors. In turn, this reduces heat generation. Less heat means that the components can fit compactly in the device.

Thermal Management

All electronic components generate some heat due to inefficiencies. When components are tight, managing the thermal load becomes increasingly challenging.

Effective thermal management strategies are critical. These can include:

• Using high-efficiency topologies that minimize waste heat.

• Selecting components with low thermal resistance.

• Employing advanced packaging techniques that facilitate heat transfer from the components to the case or an external heatsink.

• Utilizing thermally conductive encapsulation materials.

A design that efficiently removes heat can operate at higher power levels within a smaller volume, thus maximizing power density.

Component Quality and Design

The choice of components plays a pivotal role. Advancements in semiconductor technology, such as the use of gallium nitride (GaN) or silicon carbide (SiC) transistors, allow for higher switching frequencies. Higher frequencies enable the use of smaller magnetic components (inductors and transformers), which are typically the bulkiest parts of a converter.

Furthermore, the overall circuit design, or topology, has a significant impact. Advanced topologies like resonant or quasi-resonant circuits can achieve higher efficiencies than traditional designs, reducing heat generation and enabling greater miniaturization. A well-executed layout that minimizes parasitic inductance and capacitance also contributes to better performance and a more compact form factor.

Encapsulation

Encapsulation, where the entire circuit is potted in a solid compound, serves multiple purposes. It provides structural integrity, protects components from shock and vibration, and can improve thermal dissipation by conducting heat away from the core components to the outer surface. The choice of encapsulation material and process is a critical element in the quest for higher power density.

How To Calculate Power Density

Calculating power density is a straightforward process, but it provides invaluable insight when comparing different power solutions. The fundamental formula is simple:

Power Density = Power Output (W) / Volume

This formula, widely used in the power electronics industry, provides a standardized metric for evaluating converter performance. Here’s a step-by-step breakdown of the calculation:

Determine the Rated Power Output

Find the converter’s nominal power output in watts (W). The value will be on the manufacturer’s datasheet. The rated power output is the amount of continuous power the device can deliver under specified operating conditions.

Calculate the Physical Volume

Measure the converter’s dimensions using consistent units. Multiply the length, width, and height to determine the volume.

Divide Power by Volume

Divide the power output by the calculated volume. The result is the power density, expressed in W/in³ or W/cm³.

Find Miniature HV DC-DC Converters at HVM Technology

Power density indicates a converter’s design quality and suitability for space-constrained applications. By carefully considering the factors that influence power density and knowing how to calculate it, the DC-DC converter will provide the performance needed to function correctly.

At HVM Technology, we specialize in engineering and manufacturing miniature HV DC-DC converters that offer industry-leading power density without compromising reliability. Explore our innovative solutions and discover how our expertise can power your next breakthrough. Contact HVM Technology today to discuss your specific high voltage requirements.