Moodz' Awesome Gold Pulse Induction Version 3 - MAGPI V3 Project

[KingJL]

Maybe we should include in the trouble shooting list though?

That would be a good idea!

I have just built up unit no 4 ... 3 previous no failures yet. This one is fitted with the 5.6 mh inductors on the audio filter.

I would be interested in the outcome!

...just noticed for the Erratum list ... I am using 10K for R13 and R14 instead of 1 K. and the big filter caps are 470 uF.....

Thanks... will change my schematic accordingly.

[Dean Sarelius]

Thanks Jim ... I had better start an Erratum list ....I have been using this configuration for years with prob hundreds of different boards and mostly programmed with the PICkit 3. Maybe we should include in the trouble shooting list though?

I have just built up unit no 4 ... 3 previous no failures yet. This one is fitted with the 5.6 mh inductors on the audio filter.

just noticed for the Erratum list ... I am using 10K for R13 and R14 instead of 1 K. and the big filter caps are 470 uF..... the filter caps are not super critical with linear regs. They need to be there of course.

... and the 9.1 volt zener across the bsp230 bias cap. :-)

moodz

Hi Moodz,
In addition to the errata list just got a couple of questions.
Q1 - Label DRV pin 5 of U11 (OUT_B) doesnt appear to have a connection within the schematic..?
I think this may have somthing to do with your comments "U11 is not needed if you link pin 7 U11 to pin 7 of U6"..just not sure what it all means..?
Cheers
Dean

[moodz]

May I suggest you remove 1uF from PIC32 pin 5 (MCLR#)... it MAY interfere with in circuit programming/debugging (reference PICkit 3 manual).

Thanks Jim ... I had better start an Erratum list ....I have been using this configuration for years with prob hundreds of different boards and mostly programmed with the PICkit 3. Maybe we should include in the trouble shooting list though?

I have just built up unit no 4 ... 3 previous no failures yet. This one is fitted with the 5.6 mh inductors on the audio filter.

just noticed for the Erratum list ... I am using 10K for R13 and R14 instead of 1 K. and the big filter caps are 470 uF..... the filter caps are not super critical with linear regs. They need to be there of course.

... and the 9.1 volt zener across the bsp230 bias cap. :-)

moodz

[KingJL]

"... wait a little while till people on the Geotech forum have found any errors and made suggestions ( hopefully not rude ones ) before you build one..."

May I suggest you remove 1uF from PIC32 pin 5 (MCLR#)... it MAY interfere with in circuit programming/debugging (reference PICkit 3 manual).

[moodz]

Dear moodz now is it possible to make it ? I want to make it but if it is not ready I want to wait more for pcb order, what do you think about pcb changes future ?

Hi wrtk ... I do not plan to change my PCB layout. its always a good idea to wait a little while till people on the Geotech forum have found any errors and made suggestions ( hopefully not rude ones ) before you build one.
I will post some build details of units I have built shortly. Also keep an eye on the SMD version from KingJL ... it looks really good.

moodz

[wtrk]

Dear moodz now is it possible to make it ? I want to make it but if it is not ready I want to wait more for pcb order, what do you think about pcb changes future ?

[moodz]

Thanks Moodz - I will start laying out the schematic and if there are any changes or additions required it should be relativley minor.
Regarding the NMOS or SIC devices will this change need to be factored in..?

For NMOS
The biasing is setup for grounded coil and +positive TX supply ( ie PMOS ).
NMOS would require a negative TX voltage for grounded coil.
Supplies to the preamp loops would need changing.
Various diodes would need reversing.
The voltage mutliplier would need to be pos instead of neg.

If that was done then no problemo.

short answer .. prob save it for V4
moodz

[moodz]

First iteration of a miniature MAGPI v3 in SMD. Board is 100 mm x 50 mm.

Really excellent work ... one thing I might mention is that the filter for the balanced PWM audio is a simple RC low pass. ( x 2 ) ... though a single leg can be used to ground with a DC blocking cap ( non polarised ) of suitable value.
If an RL low pass is used then considerably more audio power will be delivered. ( ie louder ) I have used a 5.6 mH inductor with 10uF cap or 1 uF cap for higher freq response for 32 ohm headphones.
Might be worth allowing for the inductor or resistor option in the filters .... the inductor packages will generally take up a bit more space than a resistor.

moodz

[Mdtoday]

Great work James!

[KingJL]

Paul, thank you for your answers... the rearranged diodes a great change. I think I will layout a compact pin pointer. is a great

First iteration of a miniature MAGPI v3 in SMD. Board is 100 mm x 50 mm.

[pustareka]

moodz
Minelab crasher ?

[waltr]

Thanks Moodz - I will start laying out the schematic and if there are any changes or additions required it should be relativley minor.
Regarding the NMOS or SIC devices will this change need to be factored in..?

I do recommend running traces from ALL unused PIC32 pins to a header or at least to thru-hole pads. This allows easy modification and/or adding/chaning a feature using another pin.

[eclipse]

As for the SIC look for UnitedSIC devices. They are driven by regular mosfet voltages and provide drop in upgrade /low Coss, low Rds, etc/

[Dean Sarelius]

Thanks Moodz - I will start laying out the schematic and if there are any changes or additions required it should be relativley minor.
Regarding the NMOS or SIC devices will this change need to be factored in..?

[moodz]

Hi Moodz,
Just been reviewing your source code it is very neat and easy to read, I am sure you have written code once before right...just kidding.
Have a few questions re main.c
Q1 - PIN 25 = Not Used = 400kHz pwr sync clock << I gather there was no need to use the power sync option on pin25..?
No power sync need for liner regs :-) .... however i have another version that uses a switchmode and then it is.
Q2 - OpenTimer3 comments refer to OpenTimer5 but gather that these comments are applicable to Timer3 is that correct..?
Yes .. I think I changed timers at one stage and maybe comments dont match now ... correct. ( i think )
Q3 - INT16 initialize() refers to PIC32MX250_setup_pins() but gather that both the 150 and the 250 are identical in their pin out so no problem to leave as is..?
same except for USB functionality. ( none on 150 )

FYI - I am planning to layout a 4 layer SMD version of your design and will make it available to the rest of the forum when completed.

Before I do however would prefer to base it on what you consider to be a final revision so will remain on standby.
not planning to change anything on the layout ... only the internal code dealing with serial / LCD / rotary ... so no schematic changes.
the only hardware change might be bring out the pins I didnt use on the CPU to the headers .. no biggie.

Cheers