Universal PIC switchmode status report

Universal PIC switchmode status report

Today got all functions working, but have not connected a shunt to measure output current yet (in case one wanted to know the exact value).

Here is a picture of the power_PIC with the LCD attached, and a RS232 request for 6.0V: ftp://panteltje.com/pub/power_pic/power_pic_working_img_0905.jpg

The LCD reads topline: time, voltage setpoint, and current limit value.

The bottom line reads: Output Watts, output voltage, output current.

(The clock can be used for software battery charger routines later).

Watts is zero as no current sense connected, and is simply Uout x Iout.

I have to interrupt this project now because my RGB LED strips arrived, here a picture of one: ftp://panteltje.com/pub/col_pic/RGB_LED_strip_img0906.jpg

Much brighter then I expected!

170 mA @ 12V for one such a strip, green 70 mA, red 60 mA, and blue 40 mA.

Back to powerPIC: In theory I will need an opamp to amplify the voltage across a big shunt a bit, but in practice maybe if I let the internal ADC use the PIC's internal 0.6 V reference, and as it has a 10 bit ADC with 1024 steps, that would give .5 mV resolution, or, with a 20 mOhm shunt, 25 mA resolution..... For a 10 A full scale that would suffice for this LCD. Cool, have to see if that all works, and if I can select .6 V reference for the ADC while selecting other references for other things like the comparators.

Reply to
Jan Panteltje
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Universal PIC switchmode status report

Today started a web page that will keep people interested in this project informed. the asm pre-release version is there, also a diagram, and a picture of the latest hardware experiment, > 55 W output.

Use at you own risk.

Copyright Jan Panteltje 2009-alway.

Environmental statement: No silicon creatures were killed or hurt in developing this design. One filament light bulb was flashed away as a tribute to outlawing Edison bulbs. end of environmental statement.

Reply to
Jan Panteltje

Universal PIC switchmode status report

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Reply to
Jan Panteltje

Er, wow. Has NL banned breadboard?

I guess you don't follow the rule about minimising the area of the high-current loops ;)

Reply to
Nobody

On a sunny day (Sun, 15 Feb 2009 11:45:57 +0000) it happened Nobody wrote in :

Well, eh, my experience with breadboard was eh, shallwesay this? ftp://panteltje.com/pub/of_center_holes_img_0569.jpg

In the old days I did do a complete TV horizontal deflection on a table like that, also a complete high sensitivity SB receiver.

I dunno if you ever worked in high power electronics, but a bit of wire you will usually find there, at least it was that way...

Anyways, version pwr-0.2.asm is now available for download at the above link. Re-arranged some pins, so now an extra analog input is available, using it for input voltage. If I had one more, then theoretically I could display the efficiency too. :-)

But... it will indeed have to go on a piece of PCB one day, this one makes a very nice lab supply, put a 12V gel battery in it, and it is portable to the boonies too.

Reply to
Jan Panteltje

ok, they are not really centered, but should be no problem. For low frequency stuff, I like this kind of breadboards:

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Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de
Reply to
Frank Buss

On a sunny day (Sun, 15 Feb 2009 20:26:00 +0100) it happened Frank Buss wrote in :

I have never used one of those. Looks so fragile... My wire soldered boards you can throw around and they will usually still work. Also connections are always a problem here (close to the sea, high humidity), I cannot only use switches with gold contacts for example, other ones just start making bad contact.

Reply to
Jan Panteltje

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