UCD3138: hou to achieve two power modules at the same time start based on the UCD3138

Hello, ask a question.
I would like to do a DCDC power supply based on the UCD3138  , and then the two power supply in parallel, when  input power, the hope that two DCDC power can start at the same time, that is, the output voltage set up time is basically the same.
I would like to ask how do I design hardware and software to achieve two power modules at the same time start, are  there reference cases?
Thank you.