DC / DC Converters, Applications, Challenges and Innovations

DC/DC Converters: Applications, Challenges, and Innovations

While power supplies are needed for conversion from mains voltage, DC/DC converters are typically required when there is already one DC voltage and an additional voltage is needed. In some cases, the converter acts as a voltage stabilizer for a DC input that is almost identical to the converter's output voltage. This is common when the consumer or load operates at a relatively narrow and precise voltage, while the converter receives voltage within a relatively broad range. However, as one might infer, the range of DC/DC components is relatively smaller than that of power supplies, since a converter is not always necessary if an AC-to-DC conversion is already in place.

Battery Arrays and Input Voltages of Converters in Ranges from 8VDC to 160VDC
 

Input Voltages of Converters are Far More Diverse Than Power Supplies

Input voltages for converters are much more varied than those for power supplies, which typically range between 90-260VAC to cover the entire power grid spectrum (excluding three-phase networks). In converters, the input voltage depends on the existing DC voltage within the electrical system. For example, if the control system operates at 24VDC, the input voltage for the converter will generally range from 18VDC to 36VDC. In communication systems, the DC voltage might be 48V, so the converter's input range will likely be between 36VDC and 72VDC. Systems based on 12VDC will have an input voltage for the converter between approximately 9VDC and 18VDC, and so on. Therefore, a DC/DC component manufacturer must offer different models for each relevant input voltage in each series. Additionally, in some cases, converters are required to support multiple input voltages, such as both 12VDC and 24VDC or both 24VDC and 48VDC.

One application requiring a converter with a wide input voltage range, such as 9-36VDC, is in the field of automotive or other motorized vehicles. As is known, the electrical network in passenger vehicles is 12VDC, whereas in trucks and buses, systems operate on 24VDC. Therefore, when a system needs to be installed in both types of vehicles and requires 5VDC, the necessary voltage conversion is from 9-36VDC to the required output of 5VDC. One leading manufacturer addressing this challenge is P-DUKE, which offers parallel series of converters within each standard series to support this particularly wide input range. For example, the HAE75, HAE100, HAE150, and HAE200 series in a HALF BRICK size offer both standard and wide-input versions. For instance, in a 24VDC/200W output unit, the HAE200-24S48 model has an input voltage range of 16.5-36VDC, while the HAE200-24S48W model provides an extended input range of 8.5-36VDC, allowing the converter to be powered by either 12VDC or 24VDC.

HAE200 and WAF150 Series with Wide Input Voltage Ranges

Railway Applications and the Need for Extra-Wide Voltage Ranges

One application that requires an exceptionally wide voltage range is the railway sector. In this field, an extensive DC voltage range is necessary because each country—and sometimes even each city—utilizes different operating voltages for trains. Although the voltage is consistently DC, it varies from place to place. Therefore, all equipment used in rail transport must be capable of operating on a particularly wide range of DC input voltages. Regulations have even been established to certify converters meeting these requirements, marking them as “Railway” compliant with a special designation. These specialized converters can accommodate a DC input range two, three, or even four times broader than standard converters. For example, P-DUKE’s QAE100 series offers two input voltage ranges: 9-75VDC or 14-160VDC.

Various P-DUKE Models for Railway Application Use

A Variety of Railway Models Ranging from 3W to 300W in Different Sizes

Diverse Input Voltages Present Challenges for DC Voltage Conversion

As can be seen, different input voltages create distinctions and diversity in the field of DC voltage conversion, posing challenges for manufacturers. Many manufacturers offer models that enable voltage converters to withstand high voltage surges or drops below the minimum voltage level under unstable voltage supply conditions. To meet these requirements, there are even components designed specifically for applications demanding such resilience, including military and security products. One such component can "clamp" high voltage levels that exceed the input voltage range.

P-DUKE's SSM Series: Components Providing Surge and Spike Protection

Alternatively, in the case of a drop below the minimum voltage, a component can be used that acts as a type of UPS backup unit, supporting the input voltage of the converter. This component can also function as a power supply and not just as a converter if it is connected to the output of the power supply rather than the input of the voltage converter.

Meanwell's DBUF40-24 Unit: Backup for Momentary Drops Below 22VDC

Naturally, the best solution is for the converter unit to withstand both brief high voltage surges exceeding the defined range and momentary drops in input voltage below the specified range. This indicates that there is always room for improvement.

Written by Chaim Melas
052-3231060
chaim@advice.co.il
Advice Electronics Ltd.