i used ir2117 to drive mosfet for dc dc buck converter the input for the driver is pwm from microcontroller i attached the circuit but there is a problem the output from this driver is 9v pure dc not pwm like the input

 

Is there a voltage connected to the drain of the MOSFET? It needs one. If there already is, then you likely either have a bad IR2117 or there is a wiring error.

 

i haven't connected voltage to drain , i think it should give output on the gate , there is no relation to drain.

 

The you either have a wiring error or a bad IC as I previously stated.

 

Gate voltage must be 10 V to 15 V higher than the source voltage. Being a high-side switch, gate voltage would have to be higher than the rail voltage.

 

I tried to explain (in another forum) that the problem is that he is trying to drive IR2117 input from a 0-5v microcontroller signal but according to the IR2115 datasheet (with Vcc=15v )

anything <6v is translated as low and anything >9.5 as high.
A 0-5v signal can't work, a level translator must be used to translate 0-5v to 0-15v.

 

I tried to explain (in another forum) that the problem is that he is trying to drive IR2117 input from a 0-5v microcontroller signal but according to the datasheet anything <6v is translated as low and anything >9.5 as high.
A 0-5v signal can't work, a level translator must be used to translate 0-5v to 0-15v.

So the op is apparently a slow learner.

 

Not necessarily, we all get stuck sometimes but maybe someone else can explain it to him some other way that may help him.

 

and I also tried to tell him that IR2110 has the same attached pic , however it can drive down to 3.3 volt

 

This is very funny, I reply in both forums

IR2110 recommended range for VDD is Vss+3v to Vss+20, that means that for Vss=0 the logic level supply can be as low as 3v in which case you can drive the input even with 3v

On the other hand for IR2117 the recommended range for Vcc is 10 to 20v so it can't work with 0-5v input.

 

do you show your self,Viewing strength ! are you proud of replying in two forums ?! so how could you explain what happenned in this posthttp://www.edaboard.com/thread219997.html while IR2110 working directly from microcontroller

 

@mah, please look at the "functional block diagram" in both data sheets.

The 2110 has a box called, "Vcc/Vdd level shift". This is what allows the 2110 to work at down to 3.3V logic input. this level shift pulls the low voltage up to the 10V - 20V needed to change the outputs, Ho and Lo.

Now look at the2117 diagram. It has no level shift box. This means that it takes, 10V to 20V to change the Ho and Lo.

The part of the data sheet you showed is correct, internally both devices need 10V-20V to change. It is just that the 2110 has an internal level shift allowing it to work with lower logic voltage.

Hope this helps.