Research On Key Technologies Of Monolithic Integrated High Voltage Switching Power Supply

With the rapid development of power electronic systems,power management chips,especially high-voltage switching regulators,are widely used in new energy power generation,mine systems,vehicle power supplies and other occasions.The input voltage range in these occasions is very large,the maximum input voltage may reach tens of volts or even higher,so a high-voltage power management chip is required to supply power for it.Therefore,it is of great significance to study the key technologies of high-voltage power chips.This article focuses on three key technologies of monolithic integrated high-voltage switching power supply,and applies these three technologies to a high-voltage DC-DC converter for overall verification.The main research contents of this article are summarized as follows:1.The bootstrap technology based on high-voltage NMOS power switch has been studied,and three optimization schemes have been proposed.Among them:The low-power bootstrap technology uses PMOS instead of diodes,which has a small on-state voltage drop and low power consumption;The power detection type bootstrap technology detects the input voltage of the chip,so that when V_IN is small,the bootstrap voltage can still meet the requirements;The voltage-stabilized bootstrap technology stabilizes the bootstrap voltage VBS through negative feedback to avoid unnecessary power consumption caused by insufficient drive voltage.2.The high-voltage and low-voltage level conversion technology has been studied,and three improvements have been proposed from the perspective of device size and circuit structure.Among them:the latch inverter type level conversion technology reduces the occupied area and reduces the quiescent current by forming a latch inverter structure internally;the SR latch type level conversion technology adds an SR lock at the output Memory,which solves the problem of switching asymmetry of traditional level-shifting technology;high-performance level-shifting technology combines the first two schemes,using two inverters instead of the traditional cross-coupling structure,and adding an SR latch at the output Structure,the flip time has been reduced from 23.21ns of the traditional structure to 0.96ns,and power consumption has been reduced,and flip symmetry has been also achieved.Finally,based on the bootstrap technology,a level conversion unit based on a bootstrap high-side gate drive has been designed.3.The related technology of on-chip integrated voltage regulator has been studied,study the impact of the error amplifier structure on the PSRR,the selection of the power stage,the generation of the reference voltage and reference current,the definition of various performance indicators and the influencing factors,and the pole-zero analysis and frequency compensation method,finally an on-chip integrated LDO structure with strong anti-noise ability,stable system loop,simple structure and small occupied area is designed.4.Based on the 0.5μm BCD process,the three technologies studied in this paper were applied to a high-voltage switching power supply chip XD1121,and the chip has been simulated and layouted with the Cadence platform and Hspice tools.All the indicators met the design requirements.