Among the applications for these devices are electric compressors, inverters, and switching circuits.
By Murray Slovick, Contributing Editor
An increasing number of automotive makers are offering electric vehicles in response to growing environmental awareness and rising fuel costs. This has called for an increase in battery capacity to improve driving range. Especially in Europe, higher-voltage batteries (800 V) require power devices featuring low loss and higher withstand voltages, which increases demand for both 650-V-rated and 1200-V- rated insulated-gate bipolar transistors (IGBTs).
Expanding the number of electric vehicles also advances the need for electric compressors often driven with IGBTs. Internal-combustion-engine vehicles have used the heat dissipated from the engines themselves as a source to heat the cabin.
However, the demand for systems that use circulating warm water with a positive-temperature-coefficient (PTC) heater as a heat source has been growing as well. IGBTs that operate at low frequency are commonly used in inverters and switches for these applications. Especially in electric vehicles, the power consumption of the compressor and heater affects the driving range, and, therefore, improved efficiency is desirable.
In response, ROHM announced the addition of four new automotive-grade 1200-V-rated IGBTs well-suited for inverters used in electronics compressors and for switching circuits used in PTC heaters. The new RGS series represents ROHM’s lineup of AEC-Q101-compliant IGBTs in both 1200-V-rated and 650-V-rated variants (Fig. 1).
This series delivers what’s claimed to be class-leading low conduction loss that contributes to its small size and improved applications efficiency. ROHM now offers a total of 11 devices, including 650-V devices. This series has both simple IGBT type and built-in freewheel diode type, enabling customers to select the most suitable device.
In the RGS series, an optimized device structure reduces VCE(sat) to 1.70 V, which enables approximately 10% to 15% reduction in conduction losses compared to conventional products (Fig. 2). For electric compressors and PTC heaters, conduction loss is a more important feature than switching characteristics due to the low drive frequency. ROHM points out that this low-conduction-loss IGBT enables compact and high-efficiency designs. The 1200-V-rated devices also feature a short-circuit resistance of 10 μs (Tj = 25℃), which ensures reliability for automotive applications.
All parts in the new series are available now.