TDK: well equipped for 48V
Some attractive advantages are offered by 48V technology for vehicles: It helps to reduce overall fuel consumption, reduces the environmental impact and can even improve the engine performance. The central component for this is a powerful buck-boost converter. With its power inductors and aluminium electrolytic capacitors, TDK offers key passive components for this purpose.
In view of the growing demands to reduce fuel consumption and CO2 emissions, 48V technology offers attractive advantages. They are not a replacement for existing 12V architectures, but rather represent more of an extension to the 12V systems for handling powerful loads and is coupled to these systems by means of a buck-boost converter.
Efficient coupling by means of buck-boost converter
The most important component of a combined 12/48V system is the buck-boost converter which permits the bidirectional flow of energy between the two voltage levels.
TDK has developed two new series of EPCOS power inductors for the storage and smoothing chokes in the converters. The ERU 27 series of inductors, for example, are SMD components. They are characterised by their high current capabilities and very compact footprint of just 30mm x 27.8mm (Figure 2, right). Their insertion height is 15.5mm or 20.3mm, depending on their inductance value. This compact design is made possible by the use of a flat winding that offers a high volume fill factor. The inductors are available in six versions covering an inductance range of 3.5μH to 15μH. Their saturation current varies between 19A and 49A.
As an alternative to the SMD types, the EPCOS ERU 33 types with their PTH terminations can also be used (Figure 2, left). This series offers a rated inductance of 3.2μH to 10μH and – depending on type – they are even designed for a saturation current of 79A at an ohmic resistance of 0.85mΩ. The dimensions of these power chokes are 33mm x 33mm x 15mm. All the above types are suitable for operating temperatures ranging from -40°C to +150°C. They are also RoHS-compatible and qualified to AEC-Q200. In addition to the standard ERU 27 and ERU 33 types, customer-specific types with other inductance values can also be offered.
Extremely vibration-resistant capacitors with high ripple current capability
Apart from the inductors, the key components in buck-boost converters are robust aluminium electrolytic capacitors for storage and smoothing. The EPCOS B41689 and B41789 series (Figure 3, below) are specially designed for the stringent demands of automotive electronics. They are characterised by their extremely high vibration strength of up to 60g. The soldering star design and the version with cathode plate contacts on both ends of the capacitor enable optimised mounting with low ESL values.
Thanks to their multiple internal contacts, these capacitors also feature low ESR values, which results in a higher ripple current capability and lower losses. Depending on type, the continuous ripple current capability of these capacitors at a case temperature of 125°C reaches values of up to 29.5A. The automotive series are designed for rated voltages of 25V, 40V (for 12V) and 63V (for 48V). With these voltages they can be used in the new on-board power systems at both voltage levels. The capacitance range extends from 360μF to 4500μF.
If you would like to discuss your requirements, get in touch with the team in your local language.