Adaptive current source driver for high-frequency boost converter

The elimination of electromagnetic emissions (EME) in switch mode power supplies (SMPS) has high importance especially in automotive applications. External filters, spread spectrum techniques and the output driver circuits are the main methods to influence the switching behaviour of SMPS. This paper presents the concept of an output driver with adaptive current source control for high frequency SMPS and its study regarding electromagnetic compatibility (EMC) performance. The advantage of proposed circuit in comparison to the previous solutions is adjusted driver gate current based on the information of the gate voltage slope without involving the complex digital control scheme which requires to sense and to digitize the information of the switching current, switching node voltage and gate voltage. Moreover, this concept allows to control the programmed driver switching time independently from external parameters (load current, input voltage, ambient temperature). To verify the advantages of the proposed concept, the boost converter with the digital controller, 8V output voltage, 500-kHz switching frequency has been used.