Vishay’s new family of PWM optimized MOSFETs have been designed to give the highest efficiency available for a given on-resistance in switching applications such as dc-to-dc conversion. These new devices provide a very low gate charge per unit of on-resistance, in addition to fast switching times. The result is reduced gate drive and crossover losses, allowing designers of dc-to-dc converters to simultaneously reduce the design footprint and increase efficiency
Vishay Siliconix introduces a family of PWM optimized power MOSFETs designed to maximize efficiency in low-voltage DC/DC conversion applications. The document focuses on the Si6801DQ device, which offers reduced gate charge and fast switching times compared to conventional or low-threshold alternatives.
The note details a real-world application using the Si6801DQ paired with the Si9160BQ switching regulator IC in a synchronous boost converter for cellular telephones. It presents data showing that the PWM optimized technology provides superior efficiency and lower power losses across various switching frequencies (300 kHz to 1.8 MHz) compared to standard MOSFET technologies.
The application specifies a maximum output current of 1 A.
The switching frequency varies from 300 kHz to 1.8 MHz depending on the RC value.
The Si6801DQ switches in 4 ns, which is faster than the 11 ns switching time of a conventional MOSFET.