基于宽负载应用Boost变换器的环路补偿设计

Loop Compensation Design of Wide Load Application Boost Circuit

恒定关断时间控制模式的Boost电路因其无需斜坡补偿的优点而广受欢迎,但由于其环路存在右半平面零点,使得环路补偿变得复杂。该文采用最新的闭环时域分析方法,在不断环的情况下进行环路建模。同时根据具体应用,提出了一种具体的补偿设计的分析方法,适用于片内固定补偿的设计,可减少外围器件的选取。最后加入动态范围匹配(dynamic range match)电路,使系统可以在宽负载范围内稳定工作。该电路通过0.5μm CMOS工艺仿真验证,使得Boost输入电压在2.3~4.2 V范围内,负载电流在0.3~2 A的范围内变化时,环路能够稳定工作。

The Boost circuit in constant off-time control mode is popular because it does not require the benefit of slope compen⁃sation,but loop compensation is complicated by the presence of a right half-plane zero in its loop.In this paper,loop modeling is per⁃formed with continuous loops using the latest closed-loop time domain analysis method.At the same,according to the specific applica⁃tion,a specific compensation design analysis method is proposed,which is suitable for the design of on-chip fixed compensation and can reduce the selection of peripheral devices.The dynamic range matching(DRM)circuit is designed to the system work stably over a wide load range.The circuit is verified by a 0.5um CMOS process simulation,so that the Boost input voltage is in the range of 2.3~4.2V,and the loop current can work stably when the load current varies from i 0.3 to 2A.