For the miniaturization and integration of Boost converter andfor the requirements of intrinsic safety

the converter is divided into three operating modes according to the minimum inductor-current

i.e.

the complete inductor supply mode(CISM)

the incomplete inductorsupply mode with continuous conduction mode(IISM-CCM)

and the incomplete inductor supply modewith discontinuous conduction mode(IISM-DCM). The output ripple voltage(ORV)in each mode is analyzed respectively

and the maximum value of ORV(MORV)is obtained for the three modes. It is concluded that the minimal inductance to guarantee the MORV to get the minimum is the critical inductance between CISM and IISM in the case of the lowest input voltage and the minimum load resistance

and that the lowest MORV is independent of the inductance. The experiments show that the MORV reaches the minimum when the inductance is approximately the theoretical value of 278 μH. The MORV keeps constant when the inductance is larger

and it increases with the decrement of inductance when the inductance is less than 278 μH. The experimental results verify the feasibility of the proposed methods.