AVR-Chat

At 08:52 PM 12/27/04 -0800, you wrote:
>yes. i connect Vss and com together oled
>(1) i have replace the 1uF ceramic cap between VB and VS to 22uF 
>electrolytic(+ -) cap.
>i found that (from osc) the waveform is ac square wave at the output.only 
>a little bit ringing at the top and bottom waveform.i increase my motor 
>voltage to 50V and still get the square wave output so i guess i solve my 
>first problem.

I assume you are talking about measuring the high side gate drive 
output?  If so, good.  You might consider adding a parallel ceramic cap to 
it for faster leading edge response but nothing you've reported suggests 
you really need it.

>(2) so can IR2110 isolate the 230V motor power supply from my atmega chip 
>which is used to drive the IR2110?do i need to add optocoupler 4N26 
>between IR2110 and atmega chip??

As long as everyone is sharing a common reference there should not be a 
problem.  Read the datasheet and watch out for voltage spikes on the 
supply  With a 230V DC bus and inductive loads another 200-300V in 
inductive spikes wouldn't be difficult.

Also watch out for shoot through, your original schematic showed no way of 
adjusting the turn-on and turn-off times.

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III