In order to meet the dual constraint requirements of safety current and anti-electromagnetic radiation power of semiconductor bridge initiating explosive devices， based on GJB 344A-2020'' General specification for insensitive electric initiators''： Non-fire test standard， the electro-magnetic-thermal multi-physical field coupling model was constructed on COMSOL Multiphysics platform by numerical simulation method. By integrating the parallel shunt mechanism of negative temperature coefficient （NTC） thermistor， the loop resistance was monitored in real time and the current input was dynamically compensated. The effects of thermal safety under three working conditions of constant current 1A， constant power 1 W and double constraints 1A1W were compared and analyzed. The results show that the power of 1 A constant current condition is only 0.78 W， which deviates from the standard by 22% because the loop resistance is reduced to 0.78 Ω. The initial current of 1W constant power condition is 0.91 A， which is lower than the safety threshold. The dynamic adjustment strategy realizes the coordinated stability of current and power through closed-loop control. The heat balance temperature of the bridge area is controlled at 449.06 K， and the shunt rate is increased from 29% to 41.26% compared with the 1A constant current condition， and the shunt rate is increased by 0.6% compared with the 1 W constant power condition.