Best-in-class Automotive Power Modules (APMs), automotive MOSFETs, and automotive Gate Drivers allow customers to maximize power density, efficiency, and reliability for their 48-volt Belt Starter Generator (BSG) and Integrated Starter Generator (ISG) designs. Customers can design BSG and ISG power stages that address 5 kW up to 25+ kW for 48-volt Mild Hybrid Electric Vehicles (MHEV) using onsemi.

Mild Hybrid Electric Vehicles (MHEV) are an interim step in the evolution from the internal combustion engine (ICE) to Electric Vehicles (EV). MHEVs reduce the average CO2 emissions from vehicles by adding a BSG/ISG to augment the standard ICE, do not require any charging from the electrical grid, and maintain consumer expectations for vehicle performance. An MHEV achieves this functionality by converting to a dual battery system that provides a 12-volt battery and a 48-volt lithium-ion battery. MHEVs also implement a medium voltage to low voltage (48 volts to 12 volts) DC-DC module to charge the 12-volt battery.

The 48-volt lithium-ion battery supplies the BSG or ISG inverter power stage, while the 12-volt battery powers other existing 12-volt modules. The 12-volt battery can also be used as an alternate power source for the low power electronics in a 48-volt module. The BSG or ISG is capable of start-stop functionality, electric drive, electric boost, and regenerative power to the 48-volt battery while coasting or braking, depending on implementation within the automotive powertrain. The typical power output range for a BSG is 5 kW to 12+ kW, and an ISG is 5 kW to 25+ kW. Classification of the BSG and ISG is not enough by name alone. There are locations designated as P0, P1, P2, P3, and P4 on the vehicle, and these positions affect the method for mechanical connection, system efficiencies and losses, and functional capabilities of the BSG or ISG. While a BSG will be limited to lower power levels due to the mechanical connection of the belt, an ISG unit is capable of higher power levels because it does not have this belt limitation. An ISG either links directly to the ICE crankshaft, the input shaft of the transmission through a belt, vehicle transmission through a gear mesh, or the rear axle system through a gear mesh. BSG and ISG modules use air or liquid cooling to help with thermal management.

onsemi provides the best solutions to address your system requirements. Our premier automotive product portfolio for BSG and ISG covers Automotive Power Modules (APM), MOSFETs, Gate Drivers, In-Vehicle Networking (LIN, CAN, CAN-FD), analog signal chain (OpAmps, current shunt amplifiers, comparators), power supply ICs and System Basis Chips (SBCs).

Block Diagram


Evaluation/Development Kits


15W High Voltage Auxiliary Power Supply for HEV & BEV Applications.


40W High Voltage Auxiliary Power Supply for HEV & BEV Applications.


6V to 18V Input Isolated SiC Gate Driver Supply Using the NCV3064 Automotive Qualified Controller. Platform can be used to create isolated gate drive supply for MOSFETs with minor changes.


Gate drivers plug-and-play ecosystem

Reference Design


15W High Voltage Auxiliary Power Supply for HEV & BEV Applications.


40W High Voltage Auxiliary Power Supply for HEV & BEV Applications.

Technical Documents

Recommendations for Reliable Switching Performance Using 40V and 80V Automotive Power Modules Using Shielded-Gate MOSFETs

Ask the Expert: 48-Volt Automotive Electrical Systems Emerging

Zero-Drift Precision Op Amps: Advantages and Limitations of the Chopper-Stabilized Architecture

EMC Tests and PCB Guidelines for Automotive Linear Regulators

Low VCE(sat) BJT’s in Automotive Applications

Basics of In-Vehicle Networking (IVN)

EMI / ESD Protection Solutions for the CAN Bus