Integrated driver supply with JFET as a "linear" regulator

Nowadays MOSFET components are widely used in power converters. They are subjected to increasing requirements: electrical performances, integration, smaller volume and price. The integration process offers the possibility to reduce the price and the volume of these devices and in the same time to add some useful functionalities like sensors for protection and control. This paper presents a solution to integrate the gate driver supply. The main advantage is the energetic autonomy of these devices. This is a parallel circuit that will take the energy available across the power switch while it is in the off-state. This circuit contains a JFET and one storage capacitor. The triode-like JFET characteristics permit to use it like a regulator of the self-supply circuit. We present the possible integration of JFET with the main power switch (MOSFET). The two devices are integrated within the same die; they share the same voltage termination and follow the same technological process. The circuit analysis of the structure is provided using numerical simulations.