Could somone please check my KC Protoboard?

Bassivus · 8th November 2006, 11:49 PM

This is my first time doing something just from the schematics. Unfortunately I don't have no other than basic knowledge in electronics so it took me days to figure this out alone...

I wonder if I have done it correctly. I am opened to all suggestions.

Thanks!

Bassivus · 9th November 2006, 07:27 AM

leads, without the components:

lucpes · 10th November 2006, 10:44 AM

If you attach the schematic you might get a reply

Bassivus · 10th November 2006, 02:08 PM

Quote:

Originally posted by lucpes
If you attach the schematic you might get a reply

Here it comes!!!

philpoole · 11th November 2006, 07:35 PM

Hi Bassivus,

Looking briefly at it, it looks good.
Glad you're thinking about star earth.
I knocked up a kwak clock quite roughly recently and started looking at the power rails with a scope to see the effects of ground bounce and ended up with nearly every component leg straight to the star ground.
(eg, r2, x1, c6 r1, r12 would each have a wire from the ground leg straight to the ground star point).
Also, it might help to have capacitance (at least c4 and c15) placed closer to the comparator, if you can.

Hope this helps, but what you have will probably work well (I've built a few before without any care to layout and they work quite well)

Cheers,
Phil

Bassivus · 11th November 2006, 10:10 PM

Thanks very much! In the mean time I have noticed that I have missed (probably accidentally erased in the corel while optimizing) the connection from the L1 to power+5V rail, but thats all corrected now!

Ivica

Bassivus · 12th November 2006, 12:52 AM

I optimized

like I was suggested, and this is the new version I came up with:

Bassivus · 12th November 2006, 01:54 PM

This makes the final version if no more mistakes are found:

gfiandy · 13th November 2006, 07:08 PM

Hi, How fast is the clock running if it is > 10MHz then the star earth topology you are using is probably not the most appropriate as the signal will follow is the field between the out bound path and the return path. In this situation a ground grid is usually better (basically this just means connect the grounds together in as many locations as possible to reduce the return ground impedance as far as possible and provide the sortest return path possible)- or if possible the logical extension for this a ground plane. At the very least I would connect from R12 accross to the ground on the driver chip so there is a return path for the curent from the oscillator that does not have to try to flow though the PSU ground.

The other thing I am concerned about is you have no ground take off for the signal leaving the PCB there should be a ground terminal next to the output signal terminal this should return to the ground on the driver chip not the star (In your case this is the centre point of the two decoupling caps C15 and C4). Stars do not work well at high frequencies you should think of the signal following in the field between the ground return and the signal trace and try to make the field area as small as possible.

Regards,
Andrew

Bassivus · 13th November 2006, 07:39 PM

Hello,

Thanks very much for the advice! Last time when I have posted I almost have put to the question the situation with R12 and C4/C15 ground, that you just have explained! Great!

If I have understood correctly it should be OK/good to connect R12 GND to the center point of ground between C4/C15 and than jumper/connect to PSU ground center?

Regards, Ivica

10th November 2006, 10:44 AM	#3
lucpes diyAudio Member Join Date: Dec 2003 Location: Iasi	If you attach the schematic you might get a reply __________________ Deep down inside.

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11th November 2006, 07:35 PM	#5
philpoole diyAudio Member Join Date: Oct 2004	Hi Bassivus, Looking briefly at it, it looks good. Glad you're thinking about star earth. I knocked up a kwak clock quite roughly recently and started looking at the power rails with a scope to see the effects of ground bounce and ended up with nearly every component leg straight to the star ground. (eg, r2, x1, c6 r1, r12 would each have a wire from the ground leg straight to the ground star point). Also, it might help to have capacitance (at least c4 and c15) placed closer to the comparator, if you can. Hope this helps, but what you have will probably work well (I've built a few before without any care to layout and they work quite well) Cheers, Phil

11th November 2006, 10:10 PM	#6
Bassivus diyAudio Member Join Date: Aug 2004 Location: Novi Sad, Vojvodina	Thanks very much! In the mean time I have noticed that I have missed (probably accidentally erased in the corel while optimizing) the connection from the L1 to power+5V rail, but thats all corrected now! Ivica

13th November 2006, 07:08 PM	#9
gfiandy Audio Engineer diyAudio Member Join Date: Jul 2003 Location: Cambridge UK	Hi, How fast is the clock running if it is > 10MHz then the star earth topology you are using is probably not the most appropriate as the signal will follow is the field between the out bound path and the return path. In this situation a ground grid is usually better (basically this just means connect the grounds together in as many locations as possible to reduce the return ground impedance as far as possible and provide the sortest return path possible)- or if possible the logical extension for this a ground plane. At the very least I would connect from R12 accross to the ground on the driver chip so there is a return path for the curent from the oscillator that does not have to try to flow though the PSU ground. The other thing I am concerned about is you have no ground take off for the signal leaving the PCB there should be a ground terminal next to the output signal terminal this should return to the ground on the driver chip not the star (In your case this is the centre point of the two decoupling caps C15 and C4). Stars do not work well at high frequencies you should think of the signal following in the field between the ground return and the signal trace and try to make the field area as small as possible. Regards, Andrew

13th November 2006, 07:39 PM	#10
Bassivus diyAudio Member Join Date: Aug 2004 Location: Novi Sad, Vojvodina	Hello, Thanks very much for the advice! Last time when I have posted I almost have put to the question the situation with R12 and C4/C15 ground, that you just have explained! Great! If I have understood correctly it should be OK/good to connect R12 GND to the center point of ground between C4/C15 and than jumper/connect to PSU ground center? Regards, Ivica

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