hi,all.The buck circuit using half-bridge will burned after power on if no pwm in.Two MOSs and IR2103 burned.But if there is 100khz 50% pwm ,the circuit can work normally. If no pwm in,HIN and LIN are high level,the bootstrap capacitor can not charge. So i think no MOS can be on. However,the fact is my circuit is burned.Sadness.

 

Look at your circuit again. You have the same input on both the Hin and Lin at the same time, this causes what is called 'shoot through' it is what is causing the mosfets to "burned". They can't be on at the same time. Google"shoot through".

 

IR2103 has the deadtime,and the time is 560ns.

 

You have the same input on both the Hin and Lin at the same time

That should be ok in theory, because Hin is active high and Lin is active low. In practice, the inbuilt 560nS dead-time may be inadequate for FETs with a high Cgs value.

 

That should be ok in theory, because Hin is active high and Lin is active low. In practice, the inbuilt 560nS dead-time may be inadequate for FETs with a high Cgs value.

I was to fast to answer I guess, didn't look at the data sheet for the mosfet driver. Most of the ones I'm familiar with have both of the inputs as a high when active.