Integrating power semiconductors components is standard industry practice to reduce size, reduce cost and improve reliability. A similar approach is now possible with power resistors, courtesy of Austrian resistor manufacturer EBG.
Multiple resistors of similar or differing values
Thick-film power resistor modules from EBG allow multiple power resistors, of similar or differing ohmic values, to be integrated into a single package, reducing size, increasing reliability and reducing cost. Increasing the level of package integration reduces the overall solution size. Reducing the number of solder joints and thermal interfaces increases reliability.
Fewer interfaces means reduced operational costs
Fewer interfaces, screwed or soldered, means less chance of reliability or manufacturing problems. Any thermal interface (i.e. a connection between the bottom of the resistor and the heat plate) requires thermal paste, which adds time, cost and complexity to manufacturing operations. Reducing the number of components by using integrated resistor modules means fewer components, reduced operational cost and time, and less manufacturing variability of the final product.
How it works
- EBG screen-prints resistive elements onto a substrate of aluminium oxide or, for high-performance applications, aluminium nitride.
- The resistive ink is baked to cure it.
- An additional dielectric layer is printed to cover the conductive ink.
- Connecting wires are soldered into place.
- The assembly is housed.
High power resistor modules from EBG
EBG offers baseplate-cooled packages, from 50W to 2000W, designed to house multiple resistive elements. The 50W rated AXP-50 series allows four connections, which equate to six different configurations of up to three resistors. In a similar fashion, the ULX-800 uses a slightly larger footprint to deliver a maximum rating of 800W.
Maximum rating – single vs multiple
When just one ohmic value is required, all the available surface area is used to fabricate the single resistor, which maximises the power rating all the active area is used. When multiple resistors are required, these are printed two or three separate areas on the substrate. The unused space between the layers, necessary to maintain isolation, reduces the maximum possible rating of the part. Therefore, multiple resistors have a lower maximum rating than a single one in the same package.
Simple and complex configurations
The simplest, single element, rated for the full power of the package, with just two terminals. If the application needs two resistors, with reduced power per element, the same package can be configured with two 20W elements. In larger packages like the ULX series, this can be two 300W elements or three 150W elements. The most complex configuration is three elements, which are either independent or form a div.
AXP-50 resistor configurations
ULX800 resistor configurations