It was common to use relay based battery switches in 12V or 24V networks, and the selection criteria was mainly based on cost. In Micro-Hybrids (12V+12V) and trucks (24V) vehicles, there is a trend towards semiconductor based battery switches. In multiple voltage level networks, a semiconductor based battery switch gets special attention particularly in P2-P4 architectures. Not all 48V MHEVs will be equally easy to address with semiconductor solutions. Infineon MOSFETs and gate drivers are key ingredients to highly reliable battery switches. Below table gives an overview about the main reasons for semiconductor based battery switches.
Figure 1: Why using semiconductor based battery switches
Today, applications profit from existing and proven solutions equipped with 40V MOSFETs – mainly used in 12V/24V systems. Infineon provides a demonstrator with high efficiency and equipped with MOSFET protection TVS diodes. Higher battery voltages (>36V) can be achieved by “Level Shifting” of the ground connection. A bipolar transistor placed between the ground connection of AUIR3242 and the module ground supports 48V systems. 80V/100V MOSFETs are to be used to evaluate a 48V battery switch use-case.
Figure 2: 24V Demonstrator that can be used to evaluate 48V battery switch use-case
Complete 48V portfolio
Infineon offers a complete and broad system of chipset solutions – from microcontrollers, voltage regulators, and transceivers to sensors, smart power drivers and very low-resistance MOSFETs – for 48V battery disconnect applications.
Selected product highlights:
MOSFETs:48V applications are driving a high demand for 80V and 100V MOSFETs for applications such as starter-generators (belt-driven or integrated), DC/DC converters, battery main switches as well as 48V auxiliaries. Infineon's OptiMOS™-5 technology offers a broad portfolio of low RDS(on), scalable MOSFETs in various packages.
For high power requirements the MOSFETs in leadless TOLL package are offered for standard Cu substrates, while as alternative the TOLG package is targeting Al core IM substrates and Cu based substrates in conjunction with very high thermal cycle requirements. Both packages are footprint compatible and provide the highest current capability on a 10x11 mm2 footprint.
Next to these two package options, the TOLT package is supporting top side cooling on ECU level.
For medium and low power requirements like in DC/DC converters or at the 48V auxiliaries, the MOSFETs in 5x6 SSO8 package or in the 3x3 S3O8 package do complement Infineon’s MOSFET portfolio.
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