Dear mehtarock026
Hi
I think your circuit has some problems . are you familiar with float ground ? your 12 volt should be isolated from 5 volt section ( it's ground ) and you should use 2 power supply with 12 volt and separate grounds ! for example if you have supply number 1 , and supply number two , the ground of supply number one should connect to the cathode of thy1 and thy2 and thy3 . and ground of supply number two should be connected to the cathode of thy4 and thy 5 and thy6 .
by the way , there is another way , that called driving with pulse transformers ( the small transformers that designed for this aim , but you'll have some problem with them , and you'd better to use optocoupler and two separate ground . ( you can achieve these supplies from two independent transformers ( 300ma is enough ) or a transformer with three independent windings . first one primary and another : 2 independent secondary .
Best Wishes
Goldsmith