About Transim. Transim , Inc. is a privately held company that develops advanced simulation software for the designer of electronic systems. The leader in switch-mode power supply ( SMPS ) simulation , Transim reduces the barriers to simulation through solutions that significantly reduce the time and expense of power electronics system development and shorten design cycles. The company's core product , SIMPLIS , a family of powerful tools designed specifically for SMPS design , is the driving force behind Transim products superior speed and accuracy. Established in 1991 , with technology developed by business and academic partnerships , Transim serves a Fortune 100 customer base.