need help , IGBT (IR2110 ) driver problems

[m.heshmat]

i made a igbt driver using IR2110 , but i Face a lot of problem such

when i connect the circuit in away apearing in picture the output of two driver is no thing !!




anyone can tell me what is the problem ??

 

[Orson Cart]

Make sure you turn the lower devices on for 100us to allow the upper bootstrap caps to charge prior to normal operation, if you run the high side only the top sides will stop due to UVLO on the 2110, so you need a circuit where the bottom side devices are turned on often enough to refresh the upper bootstrap caps....

 

[m.heshmat]

I`am sorry I couldn`t get it ... please explain with scheme how can I modify the circuit .
Thanks in advance ,

 

[applecat2411]

i also got this problem, is that you mean, with Vcc connected,
first touching the gate pin of the MOSFET with a 15V source an instant, then leave it off,
after that, the output waveform would appear?

 

[ArNvC]

I think a large enough capacitance must be chosen for bootstrap so that it can supply the charge required to keep IGBT1 on. Bootstrap cap must also not be very large that charging is too slow and the voltage level does not rise sufficiently to keep the IGBT on. The higher the on time required, the higher the required capacitance. Thus, the lower the frequency, the higher the required capacitance for bootstrap cap. The higher the duty cycle, the higher the required capacitance.