Study On Novel Half-bridge Power ICS

Microminiaturization and intelligence have become the development trends ofpower semiconductors, and smart power IC (SPIC) has been developing rapidly withthese trends and now it has been widely used in lighting, industrial control, computer,aerospace equipment, defense electronics, and a variety of consumer electronics, whichhas become the most active research field of power semiconductors. In today’s advocacyof energy-saving, as well as the trend electronic equipment microminiaturization, thepower consumption, cost, size and reliability of SPIC have become a matter of concernfor more and more people.After discussing the status and development trends of domestic and foreign powerelectronic technologies and SPIC, the above-mentioned problems are studied in thisdissertation. Based on the―optimum variation lateral doping (OPT-VLD)‖theory andpatents which had been proposed by academician Chen Xingbi, LDMOS devices andlateral low side and high side power devices are designed in this dissertation. In themeantime, a new high-voltage level shifter circuit and the isolation technology for thehigh voltage devices of a half bridge power IC are also proposed. This dissertationfocuses on the novel half-bridge power IC without using the traditional high voltagelevel shift circuit, as well as its low-voltage CMOS circuit and low-voltage powersupply circuit realization methods. Moreover, in order to improve reliability of lateralpower devices, two lateral power devices with both types of majority carriers forconduction are also proposed. Base on the support of Ph.D. Programs Foundation of theMinistry of Education of China, the main work of the author is as follows:1. Based on the―OPT-VLD‖theory and the patent of―lateral low-side andhigh-side high-voltage devices‖which had been proposed by academician Chen Xingbi,LDMOS devices and lateral low side and high side power devices are designed by theauthor. And an experimental frabrication was made to verify the devices. In themeantime, a new high-voltage level shifter circuit which utilizes active resistors tosubstitute the conventional polysilicon resistor is also proposed, thus the new levelshifter circuit not only saves chip area, but also improves its reliability.2. Based on the patent "a semiconductor device" proposed by academician ChenXingbi, the isolation technology between the two high voltage high low side powerdevice and the two high-voltage devices of level shifter circuit is studied, and the fourhigh high-voltage devices can be fabricated in adjacent voltage sustaining area, which not only saves chip area, but also solves the high-voltage interconnection in theconventional structure. The solution is verified with MEDICI and DAVINCI, and thesimulation results show its feasibility.3. Two methods of realizing a novel half-bridge power IC without utilizingconventional high voltage level shift circuit are proposed. The two methods are bothbased on the idea of sensing signals within the chip. Specifically, a high voltage PMOSis integrated in the low-side n-LDMOS power device, when the PMOS is switchedunder the controlling of the tub circuit a pulse signal is sensed, which can be used forcontrolling the low-side n-LDMOS after being processed by a low voltage circuit. Sincethe conventional high voltage level shifter circuit is no more needed in the newhalf-bridge power IC, not only saves considerable chip area, but also reduces powerconsumption and eliminate parasitic effects of traditional high voltage level shift circuit,which increases the reliability of the power IC.4. The CMOS low-voltage circuits of the half-bridge power IC which includingpulse signal generator and dead-time control circuit are designed. In the meantime, thepositive low voltage power supplies for the CMOS circuits and a new undervoltagedetection method with relevant circuit are also proposed, based on the patent "lowvoltage power supply" of proposed by academician Chen Xingbi. In order to improvethe performance of the positive low voltage power supply, a voltage regulator circuit isalso presented. Since the control voltage of the PMOS’ gate driving circuit is negativereferred to the tub voltage, thus a circuit for transforming the positive low voltagepower supply to a negative low voltage power supply is also proposed, and the obtainednegative low voltage power supply can be used for providing energy for the PMOS’gate driving circuit.5. Based on the patent of "a semiconductor lateral device and a high-voltagedevice" which proposed by academician Chen Xingbi, the LDMOS device with bothtypes of majorities for conduction is studied. Commonly, the device is a dual-gate,four-terminal device. Thus, in order to change the four-terminal device to three-terminalone, two methods with sensing a control signal inside the chip are proposed. Moreover,a comparative study between the three-terminal np-LDMOS and the n-LDMOS is alsoproposed in this dissertation.