How to improve power conversion performance with new MOSFET technologies

To meet the demand for increasing energy efficiency in switching power conversion systems, superjunction MOSFETs have become preferred devices for energy-conscious designers. Superjunction technologies allow reduced die sizes enabling designers to reduce space and increase current density. However, new demands are coming to the fore, such as improved noise performance.

Reducing electromagnetic noise emission is desirable in high-end power supplies for equipment such as LCD TVs, LED lighting, medical power supplies, notebook power adapters and power supplies for tablets.

Toshiba's Deep Trench MOSFETs (DTMOS) devices have led the market in terms of performance for some time. The latest (fifth-generation) DTMOS V superjunction devices deliver a well-balanced ratio of lower noise and switching performance through a modified gate structure and patterning, resulting in increased reverse transfer capacitance between gate and drain (Crss or Cgd).

Emitted noise is comparable to competing low-EMI devices, while DTMOS V delivers the superior on-resistance that characterises superjunction technology. Fifth-generation N-channel, 0.38mΩ-class 600V devices used in a PFC circuit, show a significant EMI reduction.

The new devices bring other substantial benefits to power designers including a 30% improvement in the fundamental figure-of-merit (FOM) of on-resistance x chip size (R_on*A).

Also, the effects of temperature on R_DS(ON) are reduced, ensuring more consistent performance. When compared to competitive devices and previous DTMOS generations, R_DS(ON) is 15% lower, at high temperatures.  Therefore costs can be saved through less simpler heat management.

The body diode achieves fast recovery times, even at high temperature, resulting in lower power losses, less heat generation and a more thermally efficient design.

The superjunction process also reduces the output capacitance, C_OSS, by 12%. This leads to a reduction in the waste energy being stored in the device that has to be dissipated during each and every switching cycle; making DTMOS ideal for the fast-switching and resonant topologies commonly found in power designs, even at partial load operation.

To find out how DTMOS V technology can help reduce EMI and improve performance of your power switching applications, please click here: