Design Of A Driver Chip Applied To Wireless Charging

With the rapid development of power electronics technology,wireless charging technology has more and more broad development space and application prospect.The reliability and efficiency of wireless charging technology are mainly determined by the transmitting chip,and the driving circuit plays a large role in the transmitting chip.And integrated chip design will be the main trend of wireless charging development in the future,so the driver chip design that integrates the driving circuit with the protection circuit and the power tube will become more and more important.The integrated driver chip is small in size,high in reliability and high in efficiency.This paper is based on this demand to design a driver chip that integrates dual half-bridge and four power switches.This design uses a twoway symmetrical design,each of which can be individually controlled to enable,bootstrap and drive,and each of which is equipped with independent overcurrent protection and short circuit protection.The chip uses a highprecision reference source and current sampling circuit,and also has protection circuits such as undervoltage protection,overvoltage protection and overtemperature protection.To solve the problem of low efficiency of traditional dead-time control circuit,this paper uses logic gates and level shifting methods to detect the gate voltage of the upper and lower bridge power transistors.The gate voltage is fed back to the control terminal through the level shift and the logic gate,thereby avoiding the situation that the upper and lower bridge power tubes are turned on at the same time.On the one hand,it can prevent the burning of the power tube;on the other hand,it can reduce the dead time and improve the emission efficiency as much as possible.In order to reduce the conduction loss of the bootstrap device,this paper uses NMOS tube to replace traditional diodes as bootstrap device,so that the turnon voltage of the upper and lower bridge power switches can reach 5V in the entire input voltage range.The driver chip designed in this paper uses TSMC0.18?m 5V/12V BCD process for layout drawing and tapeout,and puts it on a wireless charging PCB board for testing.The results show that in the input voltage range of 5V-12V,the transmission efficiency is as high as more than 84.12%,the static power consumption is as low as 478?A,and the dead time is 80ns/80ns.When the input voltage is 12V,a square wave signal with an output amplitude of11.95V/11.94V can be obtained,which meets the requirements of the design index.Compared with other driver chips,it has higher integration,smaller area,and more complete functions.The high and low voltage technology used does not require high circuit design and process manufacturing,which can meet the production needs of most small and medium-sized enterprises.