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Higher Junction Temperature in Power Modules

Higher Junction Temperature in Power Modules – a demand from hybrid cars, a potential for the next step increase in power density for various Variable Speed Drives. Removing the barrier of maximum junction temperature at 150°C will allow a significant increase in power density or simplified cooling. The barrier is set by solder fatigue and wire bond lift off at intermittent operation. New Packaging technologies can eliminate the reliability issue. Future IGBT generations will take advantage of the progress in packaging and will show major improvements based on Silicon. For the application of higher temperatures in power electronics, special concern is on PCB’s and passives. When spatial temperature profiles of heat sinks are taken into account, those components can stay within their limits. Data sheets of power devices show maximum ratings in junction temperature (TJ) of 150°C or 175°C.The maximum TJ for switching conditions, i.e. inverter operation is usually 25°C less. This lower temperature TJ,op is also based on power cycling and other reliability requirements. It is the intermittent operation of power electronics, which links TJ,op to power cycling reliability

• 1.28 MB
• Jun 06, 2008