Abstract: 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.