H bridge problem

[ahmedragia21]

hi, i designed this circuit but i think it has problems , the motor works with no signals at the input , is the design correct ? but i tried to use it in the simulator ( proteus ) it works but it has an error says (transient time step too low ) and then stops the simualtion

 

[audioguru]

It won't work because the Mosfets need a gate voltage of at least 10V to turn on fully.
The max recommended supply voltage for the IC is 6V. Then the max voltage from the emitter of the transistors to drive the gates of the IRF540 Mosfets is only about +5.3V instead of 12V.
Then the voltage to the gate of the IRF6215 Mosfet is +5.4V instead of 0V.

Also, the output of U1-A is shorted to the Input 2. Pins 12 and 13 of the IC should not be joined.

Also, the 10k resistors at the gates of the Mosfets is a very high value to discharge the high capacitance of the gates. It will discharge the capacitance too slowly for PWM speed control.

 

[ahmedragia21]

thanks for the reply , but i tried and couldnt find a soultion to drive the mosfet at leat 10V using the above diagram , could you guide me please ?
thanks

 

[audioguru]

Change the circuit a little so the original transistors drive the gates with 12V then add two transistors for level shifting.

EDIT: Corrected schematic's errors.

 

[ahmedragia21]

still not working ,
i put Power transistor BJT instead of the mosfets and they worked why ?

 

[audioguru]

still not working

Sorry, I made some mistakes. It is fixed now.

 

[ahmedragia21]

worked thanks =)