A self-powered supply circuit for switching mode power supply

The paper presents a self-powered supply circuit for high-voltage switching mode power supply (SMPS), such as buck or flyback. It can make whole SMPS converters more efficient. The proposed supply circuit is realized by the energy recycling of power MOSFET switching procedure. Firstly, dV/dt at the drain terminal of power MOSFET is detected. Then a rectified current is generated by proposed structure. With the help of dynamic current matching clamping (DCMC) technique, a stable internal supply voltage is come into being. The proposed self-powered supply circuit is validated in a standard 0.35μm BCD technology, which demonstrates that the presented circuit in this paper can improve the performance of whole SMPS remarkably without using any high voltage device and auxiliary winding.