【作者】 江伟；

【导师】 贺前华； 冼剑明；

【作者基本信息】 华南理工大学 ， 集成电路工程， 2014， 硕士

【摘要】 开关电源轻巧及高高效的特点优点，可以用于各个领域。开关电源的功耗由开关功率管损耗、开关变压器损耗、整流管损耗及其它辅助电路损耗组成。由于开关功率管损耗在整个电源的损耗中所占的比重最大，本设计着重于利用软开关电路降低开关管的损耗，从而提升开关电源的整体效率。将这种软开关技术应用到LED(Light Emitting Diode)驱动，提升LED电源的整体效率。利用电容电感的谐振技术，通过变压器的漏感及开关管并联电容，为即将开通的功率开关管提供零电压导通的条件而实现了软开关工作状态。这样避免了开关管的电流电压的交叠，降低了功率开关管的损耗，提高了LED电源的效率。根据仿真的结果，在60kHz的开关频率下，开关功率管的损耗在软开关时只有其硬开关时的一半左右。采用单片机为软开关电源的主控芯片，单片机的AD输入口为电流电压反馈信号的输入口，由两个NMOS管及开关变压器组成半桥转换电路。单片机输出只有5V，并且NMOS管接高压端需要自举驱动。采用专用的芯片实现了电平转换及自举驱动。通过在两个开关管并联电容，并利用变压器的漏感对电容的充放电，实现了两个开关管均处于软开关开关模式工作。为了简化计算过程，利用计算机仿真优化电路设计。对电路的实施了多项测试工作。测试结果表明电源具有恒流特性满足LED驱动要求，电源效率达到91%以上。更多还原

【Abstract】 Switching power supply with small size, light weight and high efficiency, which has beenwidely used in various fields. Switching power supply power loss mainly by switching powertube losses, switching transformer losses, losses and other auxiliary rectifier circuit losscomponents. Since switching power losses in the loss of the entire supply pipe in the largestshare, the design focuses on the use of soft-switching circuits reduce the loss of the switch soas to enhance the overall efficiency of the switching power supply. This soft-switchtechnology will be applied to the LED(Light Emitting Diode) driver to improve the overallefficiency of the LED power supply.Use of capacitance and inductance of the resonance technology, through the leakageinductance and shunt capacitance of the transformer switch for the upcoming opening of thepower switch is turned to provide zero voltage conditions and to achieve a soft-switching state.This avoids the current and voltage of the switch overlap, reducing the loss of the powerswitch, and improve the efficiency of the LED power supply. About half based on simulationresults, in the60kHz switching frequency, switching power loss soft switching mode onlywhen their hardware switching mode.Using MCU(micro conctroller unit) as a soft switching power supply control chip, themicrocontroller AD input port to the input port of current and voltage feedback signal by twoNMOS transistors and circuit switching half-bridge converter transformers. Microcontrolleroutput is only5V, and NMOS transistors connected to the high side bootstrap driver needed.Achieved using a dedicated chip level conversion and bootstrap driver. By two switches shuntcapacitance and leakage inductance of the transformer utilization charge and discharge thecapacitor to achieve the two switches are in the Soft Switch mode.To simplify the calculation process, the use of computer simulation to optimize circuitdesign. The implementation of a number of circuit testing. Test results show that the powerLED driver with constant current characteristics meet the requirements, the power efficiencyof91%.更多还原