You are building something like this?
You definitely need a bigger power transmformer:
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value
Vs Operating Supply Voltage 18 V
Vs DC Supply Voltage 28 V
Vs Peak Supply Voltage (for 50 ms) 40 V
Io Output Peak Current (non repetitive t=0.1ms) 4.5 A
Io Output Peak Current (repetitive f>10 Hz) 3.5 A
