Utilization of Micro-isolator to Enable More Compact Inverters for Electric and Hybrid Vehicle Power Inverters
Santa Clara, Calif., April 25, 2013 — Renesas Electronics Corporation (TSE: 6723), a premier supplier of advanced semiconductor solutions, today announced the development of the R2A25110KSP intelligent power device of isolated IGBT driver for use in electric and hybrid vehicle power inverters. Incorporating newly developed Micro-Isolator isolation technology exclusive to Renesas Electronics, the R2A25110KSP makes it possible to build more highly reliable and compact systems for today’s demanding automotive applications.
Inverters that drive the electric motors in electric and hybrid vehicles comprise a power module employing motor drive elements such as IGBTs and a control circuit block with electrical isolation between the low-voltage drive electronics and the high-voltage power electronics. The market growth of power inverters has driven power modules to become even more compact to reduce size, weight and overall cost of the system. Demand is growing for solutions that integrate the isolation elements and IGBT driver circuits to enable an even greater reduction in power module size to meet the ever-increasing push for lower cost and higher performance.
Renesas Electronics has developed the R2A25110KSP in response to this market demand.
Key features of the new R2A25110KSP
- (1) Single-package solution incorporating isolation technology and high capable IGBT driver for smaller printed circuit board (PCB) footprint The R2A25110KSP has a built-in isolation feature called “Micro-Isolator,” an isolated signal transmission technology exclusive to Renesas that uses a coreless transformer configuration. Designed for automotive applications with severe ambient temperature conditions, this device has a rated channel temperature of 150°C (max.). The R2A25110KSP delivers fast switching capacity with low dispersion (meaning that the range of characteristic values is narrow), for improved efficiency in motor drive applications. In addition, capability of IGBT drive is two to four times better than that of comparable products (impedance in on state: 1.0 Ω max.), allowing direct IGBT drive without external transistors. This reduction in external components makes it possible to decrease the PCB footprint area and use a more compact inverter control board design.
- (2) Complete over-current and over-temperature protection, even when driving parallel IGBTs, for enhanced superior system reliability IGBT devices are used in parallel as drive elements in inverter systems. In many HEV/EV applications, two IGBT devices are connected in parallel to drive a large capacity motor. Therefore, the inverter system should detect both the IGBT abnormal conditions such as over-current and/or over-temperature and avoid them. Conventional isolated IGBT drivers, however, have only one over-current protection and/or one over-temperature protection; this requires larger circuit board area. The R2A25110KSP integrates both methods, enabling protection for both IGBTs without increasing circuit area.
- (3) IGBT chip temperature monitor for enhanced system reliability The IGBT chip temperature monitor circuit monitors the temperature of both IGBTs continuously and also feeds back the higher one to the MCU via Micro-Isolator. The temperature can be calculated from the duty ratio of the pulse. Other functions that are integrated include active Miller clamp and soft turn-off. The active Miller clamp prevents false turn-on when an IGBT is in off state, and the soft turn-off function turns off the IGBT gradually when an abnormal state such as over-current occurs. This IGBT turn-off function can avoid an over-voltage spike across the IGBT caused by lead and wire inductances. These features result in a higher performance-to-cost ratio in terms of smaller system footprint, better performance and improved system reliability.
Renesas is working to strengthen its product lineup in the field of three-phase motors for automotive applications. The company is expanding its active sales efforts for total solutions combining components such as MCUs and power devices.
Renesas is also moving forward with the planning and development of additional “micro-isolated” future products that meet the isolation requirements of automotive systems while additionally integrating other functionality.