CAJ | 학술논문

同步BUCK变换器在轻载模式下会出现电感电流倒灌现象,这会使得芯片的效率大大降低。针对这一问题,设计了一款过零检测电路,该电路利用MOS管工作在线性区时的沟道电阻来产生过零检测比较器的负阈值电压,从而有效地限制了电流的倒灌；还设计了边沿隐匿电路,避免电路切换时引起的误触发。该过零检测电路基于0.5μm BCD工艺,在HSPICE软件上仿真验证,当系统温度在0~85℃变化时,负阈值容差为10 mV,过零检测电路性能良好。
동보BUCK변환기재경재모식하회출현전감전류도관현상,저회사득심편적효솔대대강저。침대저일문제,설계료일관과령검측전로,해전로이용MOS관공작재선성구시적구도전조래산생과령검측비교기적부역치전압,종이유효지한제료전류적도관；환설계료변연은닉전로,피면전로절환시인기적오촉발。해과령검측전로기우0.5μm BCD공예,재HSPICE연건상방진험증,당계통온도재0~85℃변화시,부역치용차위10 mV,과령검측전로성능량호。
The phenomenon that inductor current flow backward appears when synchronous BUCK converter works in light load mode,and the efficiency of the system will be reduced. In response to this problem,a novel zero-cross detection circuit is designed. By using the channel resistance when the MOS transistor is working in linear region to realize negative threshold voltage for zero-cross detection comparator,the happening of current backward flowing is avoided. Edge occult circuit is also designed to avoid false triggering at switching moment. The zero-cross detection circuit is based on 0. 5 μm BCD technology,and has been carried on HSPICE. The simulation result shows that the negative threshold tolerance is only 9 mV when system ranges in temperature from -25 ℃ to 50 ℃,and the zero-cross detection circuit works well.