To solve the problem of reproducibility in the electrostatic discharge（ESD） immunity test

using the ESD simulating testing system

we studied the influences of charged voltage on ESD parameters such as discharge current

rise time

and induced voltage in a semicircular loop antenna under two discharge modes

namely

contact discharge method and air discharge method. The results show that

under contact discharge mode

ESD parameters are linearly proportional to the charge voltage

and the ESD parameters increase with the increasing charge voltage. Based on this linear relationship

a severity model for ESD generator is established. When the discharge mode is air discharge method

the relationship between ESD parameters and charge voltage is rather complex

under lower charge voltage

the discharge current and induced voltage increase with increasing voltage

rise time changes few firstly

and then increase with increasing voltage. As the charge voltage increases to a certain value

the ESD parameters decrease with increasing voltage. The above results show that the discharge voltage plays an important role in ESD immunity test

when doing the electronic device ESD immunity test

choice of discharge mode

as well as the using scope of discharge voltage

should be paid attention to.