Bipolar transistors

Diodes

ESD protection, TVS, filtering and signal conditioning

MOSFETs

SiC MOSFETs

GaN FETs

IGBTs

Analog & Logic ICs

Automotive qualified products (AEC-Q100/Q101)

On-Board Charger (OBC)

Whether a car is a battery electric vehicle (BEV) or plug-in hybrid electric vehicle (PHEV), one critical component is the on-board charger (OBC). This enables the charging of the high-voltage DC battery packs from various electric vehicle service equipment (EVSE) or charging stations. Those range from single-phase Level 1 residential chargers (~3 kW) to multi-phase Level 2 commercial capable of providing up to 22 kW, supporting both 400 and 800 V batteries. Of course Level 3 fast chargers provide a DC voltage direct to the battery, bypassing the OBC. However, a small highly efficient form factor is required to give manufactures the flexibility to place the OBC in different locations in various models.

  • Block diagram
  • Design considerations
  • Product listing
  • Support

Block diagram

Controllogic AC inputfrom EVSE BatteryManagementSystems (BMS) Microcontroller/Datalogger/Comms Gate drivers CAN/I-FD 400 VDC Bus 280 V - 420 V DC aaa-033744 GaNFET GaNFET Highlighted components are Nexperia focus products.

PFC boost

Primary side conversion

Secondary side conversion

ESD protection

Control logic

AC EV wallbox

Battery Management System

Select a component

To view more information about the Nexperia components used in this application, please select a component above or click on a component (highlighted in blue) in the block diagram.

Design considerations

  • Designers have multiple options for OBC conversion topologies, including single-phase / multi-phase and uni- / bidirectional 
  • Current batteries are typically 400 V, using 650 V FETs in a bidirectional OBC topology where GaN brings the highest efficiencies (for unidirectional topologies SiC diodes can be used on the secondary side
  • For 800 V batteries, need to go multi-level GaN or high-voltage SiC
  • However OBC topologies are heavily fragmented which may lead to combined 650 / 1200 V device solutions
  • PFC output defines blocking voltage of power semiconductors at DC-DC-Input and battery voltage defines blocking voltage at DC-DC-Output (650 or 1200 V)  
  • Trend towards higher OBC charging power and 800 V batteries for higher class BEV solutions, will require more 1200 V solutions

Product listing