IR2110 full bridge gate pulse not proper

Hi Ak86 ,

Please upload your symbols and models. Zip everything up and upload here.

mike

H_IR2110_TEST3.zip  Hi, I uploaded the schematic for your review.

Hello Ak86, 

you appended now the raw and the log file (which are not really helpfull). But the model and the symbol for the IR2110 are still missing. So others can not run your simulation. 

But even with the model, one likely problem jumps out at you. You turn the FETs on quickly over a diode in series with 5 Ohm. But you turn them off very slowly over a high impedant resistor of 1 kOhm.

That will give turn off times in the range of several µs, and this will sure result in bad waveforms with a 24kHz PWM. 

If you wanted to achieve a shoot through protection by this asymmetric gate driver, it's the wrong way around: for shoot through protection you would have to delay the turn on time, not the turn off time. And anyways, the time constants of the gate switch with 1kOhm is much too high for 24kHz PWM. Could be, that your FETs never really turn off. 

best regards

Achim 

Thanks Achim,

    I have solved it by adding pnp for fast turn-off but the simulation shows abrupt PWM generation and load current. I cant increase the voltage beyond 35V, when i connect with IR2110S. 10uF booststrap,SPWM(24kHz) H-bridge. Can u give an idea on the problem.H-Bridge_Unipolar_SPWM.zip

Hello Ak86, 

the additional pnp speeds up switching, but it makes the gate drive more complicated and error-prone. The push-pull output of the IR2110 is optimized to drive the gate directly - you should use it like that. Skip the diode, skip the pnp and skip the 1kOhm pulldown. If you want to slow down the switching edges somewhat, you can keep the 5Ohm series resistor, but the other components should be taken out of the circuit. 

Ak86 said:

I cant increase the voltage beyond 35V, when i connect with IR2110S.

Just to make sure: you talk about the bridge supply (V4), not any other supply of your circuit (like Vcc or Vcc++ or Vdd ....), correct? Since Vcc and Vdd have a limit at 25V. 

I'm still not able to run your simulation. Now all necessary files are included. But the netlist of your simulation still refers to a local file on your PC (Contrib\User Defined Libraries\), which is of course not accessible for me. 

What happens in your simu, when V4 exceeds 35V? Still a problem with the gate waveform? How does it look like with a standard gate drive circuit as proposed above?

best regards

Achim 

Hi Achim, I have uploaded the schematics with the changes said. Now it show error in IR2110 at the start.8750.H-Bridge_Unipolar_SPWM.zip

What do you mean with "it show error"? Do you get some error messages and the simulation stops? Then please describe the content of the error messages. 

Or does the simulation give unexpected results? Then please describe, what the results are and what you expected instead. 

For me it's not easily understandable what your intention with the circuit is and what behvaiour of it you regard as error. 

best regards

Achim 

What do you mean with "it show error"? Do you get some error messages and the simulation stops? Then please describe the content of the error messages. 

Or does the simulation give unexpected results? Then please describe, what the results are and what you expected instead. 

For me it's not easily understandable what your intention with the circuit is and what behvaiour of it you regard as error. 

best regards

Achim