Design Of A Programmable High-precision Open-loop Driver Chip For GaN Devices

At present,the power electronic system is looking for a breakthrough in the direction of high frequency and high reliability,traditional silicon-based MOSFET power devices are gradually unable to meet system requirements,while GaN power switching devices have excellent characteristics such as faster switching speeds and higher breakdown voltage,is being valued by the market.On the other hand,the increase in switching frequency means that the switching loss of GaN power devices accounts for an increasing proportion of the overall loss.It is of great significance to reduce the switching loss of GaN devices by studying the design of driver chips.However,traditional driving schemes are mainly used to drive silicon-based MOSFETs,and are not suitable for power switching devices such as GaN transistors with low threshold voltage,small gate drive voltage safety range,and short switching time.Therefore,research on GaN gate drive circuits suitable for high reliability and high performance is the key to the development of GaN technology.This paper analyzes and studies the device structure,working principle and switching characteristics of enhanced-mode(E-mode)GaN transistors,comprehensively considering factors such as the gate drive voltage,switching control range and device reliability of the device,and adopts programmable high-precision open-loop drive strategy.In view of the short switching time of GaN devices,the design divides the switching process of GaN devices into 8 stages,and the output drive current of 255 gears can be selected in different main driving stages.At the same time,in order to achieve high-precision drive requirements,each main drive stage is further divided into more refined drive stages,which can provide fine drive currents in 63 gears.The common drive of the two can realize the precise control of GaN devices in stages.In addition,considering that the driver chip can be applied to different GaN devices,an implementation method that can be programmed to change the driving sequence outside the chip is designed to achieve the control purpose of programmable and high-precision driving the gate of the GaN device.This circuit design uses the HHBCD180 GE process,builds a system framework according to the driving requirements of GaN devices,and then conducts principle analysis and simulation verification on the index requirements of each circuit sub-module,and performs layout design and post-simulation after the overall simulation of the chip is completed.verification.The chip layout area is 2960um×4000um,and maximum output current of the chip is 4.4A.By selecting different EEPROM drive sequences,the gate drive current at each stage of the switching of the GaN device can be accurately controlled,reducing the switching loss of the GaN device.