降压变换器片内集成软启动电路设计  

Design of an On-Chip Soft-Start Circuit Integrated in Buck Regulators

作　　者：袁冰[1] 来新泉[2] 李演明[1] 叶强[2] 贾新章[1] 

机构地区：[1]西安电子科技大学微电子学院,西安710071 [2]西安电子科技大学电路CAD所,西安710071

出　　处：《Journal of Semiconductors》2008年第10期2069-2073,共5页半导体学报（英文版）

摘　　要：针对电流模降压变换器的集成化趋势,提出了一种可片内集成的软启动电路.该结构利用芯片振荡器产生的窄脉冲信号,控制微电流对片内电容间歇充电得到斜坡电压,并巧妙地利用复合比较器以较小的功耗实现了对峰值电流的限制,避免了浪涌电流,完成了软启动功能.提出的软启动电路结构简单、易于实现,减少了芯片引脚数目,降低了PCB面积,并在一款基于0.5μmCMOS工艺设计的降压型DC-DC中进行了投片验证.测试结果表明,3.6V输入1.8V输出600mA负载电流在使能140μs后芯片成功实现了软启动.Following the trend of integration in current-mode buck regulators, a soft-start circuit integrated on-chip is presented. A narrow pulse signal is generated by an oscillator. To get the ramp voltage, the on-chip capacitor is charged by a small constant current source with intervals. A multiplex comparator with low power dissipation is designed skillfully to limit the peak current,avoiding the inrush current and achieving soft-start. The presented circuit, which is concise and simple to implement, reduces the pin number and saves PCB space. A DC-DC buck converter with the proposed structure has been fabricated in a 0.5μm CMOS process for validation. The measured result shows that the chip starts up successfully in 140μs with 3.6V input,1.8V output,and 600mA load current.

关 键 词：软启动电路 降压变换器 电流模控制 浪涌电流 片内集成 

分 类 号：TN432[电子电信—微电子学与固体电子学]