Three-phase motors used in electric vehicles (EVs and HEVs) present some challenging drive requirements, not the least of which involves protecting the drive circuits from overvoltage spikes across the IGBTs that can be caused by lead and wire inductances. Renesas’ line of intelligent power devices (IPDs) with overheat and over-voltage protection have been replacing power MOSFETs in high-voltage, high-reliability automotive applications.
Renesas has just introduced the R2A25110KSP intelligent power device for use in EV/HEV power inverters. These devices use a unique magnetically-coupled Micro-Isolator that protects the IGBT driver circuitry from spikes up to 2500VRMS.
The Renesas Micro-Isolator is an on-chip transformer that relies on magnetic coupling to provide data communication in much the same way that Near-Field Communication (NFC) does in cell phones. The SiO2 inter-layer dielectric provides an isolation strength of ~700V/μm, protecting the connected logic circuitry from high voltage DC transients. All the control logic lines going into and out of the device are protected by Micro-Isolators.
R2A25110KSP devices integrate two channels each of over-current and over-temperature protection; they’re also so efficient that even in when IGBTs are used in parallel in large inverters it only requires one R2A25110KSP instead of the usual two devices. With a very low RDSON (1.0Ω max), fast switching capacity, and low dispersion, the R2A25110KSP can drive IGBTs without the need for external transistors, further reducing board space and BOM cost.
The new devices contain additional protection circuitry. The R2A25110KSP prevents over-voltage spikes from reaching the IGBTs by a soft turn-off (0.5A max), which is also triggered when an over-current event occurs. A Miller clamp prevents false turn on when the IGBT is in an off state.
The R2A25110KSP starts sampling in late April in a 38-pin SSOP package with full production planned for 1H2014.