The forward recovery of the diodes causes poor performance and high conduction loss in the multi-MHz resonant converters. A simple and efficient self-driven RGD is presented. A control stage comprised of a shutdown branch and an auxiliary switch is introduced to the RGD to block the circulating current and the lowimpedance path in the drive circuit, so that the gate voltage can achieve fast shutdown and buildup under ON-OFF operation to ensure fast transient response. Moreover, the proposed RGD generates a tunable d.c. bias to increase the peak gate voltage and extend the conduction time with the optimal R_DS(on), so that the average R_DS(on) and the associated conduction loss in the SR FET can be reduced. It also provides precise switching timing for the SR to minimize the body diode conduction loss. An isolated RGD for two MOSFETs in one bridge-leg is presented. The proposed RGD can provide two complementary drive signals to drive two MOSFETs, which can be used to drive the HB leg in FB converters. Moreover, with the negative drive voltage capability, the proposed RGD ensures high reliability in the FB converters over the previously proposed RGDs.

Chapter Contents:

• 6.1 Resonant gate drivers for multi-megahertz isolated resonant converters
• 6.1.1 Introduction
• 6.1.2 Challenges for the SR drive in the multi-MHz isolated resonant converters
• 6.1.2.1 The multi-MHz isolated synchronous class-Φ2 converter
• 6.1.2.2 Challenges for the SR drive and problems of the conventional RGD
• 6.1.3 Proposed self-driven RGD for the SR
• 6.1.3.1 Self-driven level-shifted RGD for the SR
• 6.1.3.2 Problems of the level-shifted RGD under ON-OFF control
• 6.1.3.3 Proposed ON-OFF controlled level-shifted RGD for the SR
• 6.1.3.4 Design of the level-shifted RGD
• 6.1.3.5 Loss analysis of the SR with the proposed RGD
• 6.1.4 Experimental verification and discussion
• 6.2 A high-frequency dual-channel isolated resonant gate driver with low gate-drive loss for ZVS full-bridge converters
• 6.2.1 Introduction
• 6.2.2 Review of gate-drive circuits
• 6.2.2.1 The conventional voltage source drivers for the FB converters
• 6.2.2.2 Candidates of the RGDs for the FB converters
• 6.2.3 Proposed resonant gate driver for FB converters and principle of operation
• 6.2.4 Loss analysis and optimal design
• 6.2.4.1 The gate drive loss with the proposed RGD
• 6.2.4.2 The gate drive loss comparison between the proposed RGD and conventional VSD
• 6.2.4.3 The switching loss comparison between the proposed RGD and conventional VSD
• 6.2.4.4 Optimal design for the proposed RGD
• 6.2.4.5 Dead time control in the proposed RGD
• 6.2.5 The comparison between the proposed RGD and previous gate-drive circuits
• 6.2.5.1 Operation comparison between the proposed RGD and conventional transformer coupled VSD
• 6.2.5.2 Comparison between the proposed RGD and conventional VSD with gate charge
• 6.2.5.3 Applications extension
• 6.2.6 Experimental results and discussion
• 6.3 Summary
• References

Inspec keywords: resonant power convertors; switching convertors; reliability; driver circuits; transient response; minimisation

Other keywords: SR FET; resonant gate drivers; auxiliary switch; transient response; circulating current; low-impedance path; MOSFET; switching timing; body diode conduction loss minimization; HB leg; forward diodes recovery; multiMHz resonant converters; negative drive voltage capability; self-driven RGD; complementary drive signals; reliability; bridge-leg; ON-OFF operation; gate voltage; tunable dc bias; conduction time; FB converters; drive circuit

Subjects: Reliability; Power electronics, supply and supervisory circuits