High-Voltage SiC Rectifier Module for Industrial, EV Use

Nexperia and Kyocera AVX will collaborate on developing high-voltage (650 V) rectifier modules using the latest silicon carbide (SiC) diode devices. The modules will be targeted for high-frequency power applications in the 3 kW to 11 kW (20 A at 650 V) range for industrial power supplies, electric vehicle (EV) charging stations, and onboard chargers (OBC). 

 

Charging an EV through the onboard charger (OBC). Image used courtesy of Huawei

 

Module-level integration, combined with high-frequency, thermally robust SiC diodes, will allow for smaller, lighter, and more cost-effective power conversion solutions with greater power density.    

The joint product development initiative extends a long-standing development partnership between the two companies.  

 

Rectifier Circuits

Diode bridge rectifiers are simple passive circuits in AC-DC power supplies and other power conversion circuits that help convert AC power to DC. The diodes in the bridge circuit rectify the AC input to positive polarities only, with an output storage capacitor acting as a DC energy reservoir that filters out the AC components of the power signal to generate a near DC output. 

 

   

Full bridge rectifier and capacitor convert AC to DC. Image used courtesy of Electronics Tutorials

 

In an EV, the onboard charger (OBC) converts single- or multi-phase AC power from a Level 1 or 2 charger to charge the battery pack via the DC battery bus. Battery bus voltages have typically been designed for 400 V but are now migrating to 800 V and higher as designers target greater conversion efficiencies.

As with any AC-DC supply or power conversion circuit, the input rectifier is important in the power conversion process. In the case of e-mobility applications like EVs, these circuits' size, weight, and efficiency can significantly impact the performance of the end application and affect vehicle range, charge time, and cost.

 

EV onboard charger (OBC) with input rectifier. Image used courtesy of Infineon

 

Silicon Carbide Schottky Diodes

Nexperia has developed a portfolio of high-voltage (650 V and 1200 V) SiC Schottky diodes for automotive and industrial applications.

In addition to the high voltage and current (up to 20 A) capabilities, these diodes offer low forward voltage drops, fast reverse recovery, and performance up to junction temperatures of 175°C.

The standard SiC diode portfolio is available in several SMD and through-hole leaded packages, with the new rectifier modules likely constructed from tested bare die using internal wire bonding.      

 

Nexperia Silicon Carbide (SiC) Schottky diode portfolio. Image used courtesy of Nexperia

 

Rectifier Module Integration

Integrating the diode rectification circuit into a pre-packaged, tested, and qualified module will save time and reduce risk for power system designers. The higher level of integration will also translate to a smaller form factor for this essential circuit, resulting in reduced board space, higher power densities, and lower solution costs. 

 

SiC rectifier module. Image used courtesy of Nexperia

 

Based on the product concept image included with the announcement, the new module will have dimensions of 28 mm x 22 mm x 6mm, including the package leads. The low inductance package is designed to support high-frequency power conversion applications.  

An integrated negative temperature coefficient (NTC) sensor allows for real-time monitoring of the thermal performance of the module.

Samples of the new module are expected to be available in the first quarter of 2024.