Hi guys,

In the below circuit,i am facing issues trying to switch a 10KHz PWM signal.
I get a proper pulse at pin 2 w.r.t 3rd pin,but at the output side(pin 6 w.r.t pin 5) i see no pulse.
G1 is 12v w.r.t. pin 5.
At the moment GATE1 is open.I plan to connect it to an NMOS once i see an output pulse.

I tried changing the input resistance to 100 ohm, increased and decreased the values of C22 and C23 and changed the optocoupler also.




What else can i try ?

Thanks,
AK

 

hi ak,
What is the voltage supply to G1.?
E

 

Show us the complete schematic.

 

Show us the complete schematic.

That is the complete circuit,i have split it up in two ,
G1 and G2 is 12v.
the DC DC converter with provides the 12 v is given below:

If anything else is required please tell, i will post it.

 

hi,
The d/s states G1 v, 15V thru 30v, you have only 12V, perhaps the internal biassing is not correctly enabled.
E

 

As Eric writes, the supply is too low. The threshold values for under voltage protection (Table 10: UVLO) is actually around 12 Volt.

I see no reason for C32. It can be removed as you normally seeks a low GS capacity, as to reduce switching loss.

As R26, I would choose 10 K Ohm.

 

Yes ,i completely overlooked that,once i gave Vcc of 15v,i could get the output pulse.
Thanks for all the help ericgibbs and Kjeldgaard!!http://forum.allaboutcircuits.com/members/ericgibbs.73660/