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Old 10th August 2011, 11:22 AM   #101
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no indeed! its just an alim thing that i didnt respect im sure, you make vss and vaa out of B ?

edit: just realise my CSL was at min, maybe just that also, gonn borrow that oscillo tonight and check it out again

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Old 10th August 2011, 08:18 PM   #102
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no indeed! its just an alim thing that i didnt respect im sure, you make vss and vaa out of B ?
I used dropper resistors from b+ and b- for VAA and VSS.
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Old 12th August 2011, 12:49 AM   #103
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update:
realized that my amp op was dead too.. strange thing, ordered some.. didnt have spare
i made 5V with B and external diodes, work great for now
w8ting for op amps..
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Old 12th August 2011, 05:15 AM   #104
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cool to hear that
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Old 16th August 2011, 02:26 AM   #105
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got my pwm working, everything in small signal is ok, tho i dont have amplified signal, looked up csh csl, was at max, csd is waving aroung 200mv referenced to gnd. got the same signal input as output 2Vp-p (by fb ?) nothing on HO LO, and Vb referenced to -B is 0V ???? tell me what you think.. not quiet sure bout the real source

edit:
realised csd was waving in same time as pwm
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Old 16th August 2011, 06:22 AM   #106
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Vb can not be 0v compared to -B and for that you don't even need scope, are you sure you measure those two pins?

Where do you get this pwm? sounds like it wants to start, I think I had it like this, but I couldn't supply enough voltage for upper fet (since he wanted to oscillate at lower MHz range)

I still think your voltages are off, can you check that again

Also, you could be at the point I was, where I needed strong input signal, to make it operational, then it worked, untill switched off again


BUT FIRST, how much is your Cfilter and remove it... I had it, and I had problems setting any higher freq, also amp started harder
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Last edited by luka; 16th August 2011 at 06:25 AM.
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Old 16th August 2011, 11:25 AM   #107
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i didnt put Cfilter
pwm is from pin comp
i'm sure about Vb, no doubt, dont have
i didnt put R18 which charge cap on first oscillation tho
my input signal is kinda strong 2Vp-p

is CSD ok ? it is not supposed to be Vaa ?
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Old 18th August 2011, 11:59 AM   #108
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just realised it... pwm freq is about 60Hz (which is my input signal)
i guess its not normal uh ?
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Old 18th August 2011, 12:13 PM   #109
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Originally Posted by philuknow View Post
just realised it... pwm freq is about 60Hz (which is my input signal)
i guess its not normal uh ?
My PWM frequccny is about 250KHz. I can see the residual PWM on the output signal just a few volts.
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Old 18th August 2011, 06:41 PM   #110
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and I have 480k, so no, anything below 100k is not good
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