Reports show that approximately 50% of total global energy demand is used for drive motors, and with the continued expansion of electrical appliances in emerging and developing countries, this percentage is expected to increase even further. IGBTs, or insulated-gate bipolar transistors, are commonly used as switching elements in inverters that drive motors in household appliances such as refrigerators and air conditioners. Current trends focused on energy conservation have driven demand for MOSFETs with reduced power consumption during continuous operation across a wide range of applications.
To meet this demand, ROHM launched the PrestoMOS™ series of power MOSFETs in 2012. This series features the industry's fastest reverse recovery characteristics, enabling lower power consumption. As with our conventional products, this new series leverages our patented lifetime control technology to achieve an ultra-fast reverse recovery time (trr), resulting in approximately 58% power loss reduction at light loads compared to IGBT implementations. Furthermore, the increased reference voltage required to turn on the MOSFET prevents self-turn-on, a major cause of power loss. Additionally, optimization of the built-in diode characteristics has allowed us to improve the soft recovery ratio specific to Super Junction MOSFETs, reducing noise that can lead to malfunctions. Removing these barriers to circuit optimization provides customers with greater design flexibility.
What is PrestoMOS™?
“Presto” is an Italian musical term meaning “very fast.”
MOSFETs offer advantages such as high switching speed and low conduction loss under relatively low current conditions. For example, in air conditioners, they are more effective than IGBTs at reducing power consumption during continuous operation.
PrestoMOS™ is ROHM’s power MOSFET whose integrated diode features the industry’s fastest reverse recovery time (trr), contributing to lower power consumption in inverter applications.
*PrestoMOS is a registered trademark of ROHM
Keys to Improved Design Flexibility:
Increased switching speed, self-turn-on, and noise generation are conflicting phenomena, requiring customers to optimize circuits by adjusting gate resistance and other factors during circuit design. Unlike general-purpose MOSFETs, ROHM's R60xxJNx series takes measures against noise and self-turn-on, providing customers with a high degree of design freedom.
1. Implementing self-turn-on countermeasures minimizes losses.
Optimizing the parasitic capacitance inherent in the MOSFET structure has allowed us to reduce the unintended gate voltage during switching by 20%. Furthermore, the specialized design makes self-turn-on more difficult by increasing the threshold voltage (Vth) required to turn on the MOSFET by 1.5 times. This expands the adjustment range for losses due to gate resistance and other factors implemented by the customer.
2. Improved Recovery Characteristics Reduce Noise.
Generally, the recovery characteristics of the internal diode of a Super Junction MOSFET exhibit strong recovery. However, by optimizing the internal structure, ROHM's R60xxJNx series is able to improve the smooth recovery rate by 30% compared to conventional products and achieves reduced noise while maintaining the fastest reverse recovery time (trr) in the industry. This makes it easier for customers to adjust noise levels (e.g., due to gate resistance).
Gamma (figure 6)
Applications:
ACs, refrigerators and industrial equipment (e.g., charging stations)
