Microcontroller controlled power supply ....

[Bagster]

I did a Pic controlled supply as part of a piece of test equipment.
I ised a simple R2R ladder on Port c of the PIC (0-5V, 8 bit = 19.53 mV/bit) I then used a LM358 opamp as a x 5 amp, you can easily make it a x 6 to get 30V, the resolution will obviously be 30V/256 = 117mV/Bit resolution. To get the current and noise immunity from a mains converted supply, i used a power opamp from Burr Brown (OPA 544T). This with a split supply (-3V to 35V) will enable you to get 0 - 30V in 117mV steps, you can adjust the LM358 gain to give a different ratio of mV/bits.
I used a max 1681 for the negative generation, simple and easy to use.
For the Current measurement/feedback, you have a choice. Either construct a differential amplifier around a series resistor and amplify the current gain to the required ratio needed by the micro.
Accurate diff amps are tedious to design, so for speed you can use a MAX471. This little beast has an internal sense resistor and trimmed/compensated diffamp that can be adjusted by an external resistor to give the required current gain ie 1mV out for 1mA through. This is placed in series with the output.
You now have a fully programmable 0-30V psu that is a breeze to operate through a single 8bit port and a single a-d input. The PSU can have a software current limit and can provide sine/triangular waveforms if required.
All you have to watch is the power dissipation of the OPA544T. It has thermal and overcurrent protection. Texas instruments/Burr Brown will send you samples free via there web site.
I can give you some code for the reading of the A_D and the binary to decimal read out of the current taken.
I used a PIC16F877 for the design.

If you want anymore info let me know.

Hope this helps.

Bagster

 

[jetmarc]

I am looking for a SWITCHING adjustable
power supply. In a project of mine I have
very limited space available, and can not
fit heat sinks.

The output has to be 1.7v - 15v DC.

On a test prototype I use a National Simple
switcher with Xicor Digital Potentiometer
in the feedback loop. However, this is not
very accurate, and a lot of potentiometer
steps are inuseable due to the non-linear
nature of the feedback divider.

Any tips?

 

[BENOIT]

I Upload again the file digitalpsu

I join a project of a compact digital
power supply controlled by a MC68HC11A1P
and the RS232 interface of a P.C.
This power supply is done of 2 parts:
processor board and power board.
The microcontroller controls the alternative
voltage in the output of the transformer
then this voltage is rectified and filtered
to obtain a continuous signal of around 22V
from this voltage is stabilized two
voltages that will be references for the
regulation and the current sensing.
(...)
Characteristics
Preprogrammed voltages 1,5 - 3 - 5 - 6 - 9
- 12 - 15 V
I = 4A
If I Max = disjonction
RS232 control
Emission on serial line of voltage and
current
IC used :MC68HC11A1P @ 8MHZ , CD4016, MAX232,
2x16 LCD Display,LM324, 7805, 7818,
option Serial IIC EEPROM
Transistors used 2N3055, 2N2219,etc.
only the S19 SRecord file is available.
if interested in realizing it
I can translate this article into english
MB.

Uploaded file: digitalpsu.zip

 

[twinsen]

In the latest design contest @ circuit cellar I found this....

**broken link removed**

In short:

Instead of the classic transformer—with a regulator, lots of wires, and a 5-V power supply—this power supply is more like a real tool. The power supply is based on the 68HC908QT4, and features 0.6- to 20-V output voltage with 8-mV resolution, and 0- to 2.5-A output current with 10-mA resolution. Other features include short-circuit protection, adjustable current limit (5-ms response time), 5-mVPP maximum output ripple, and a 2 × 16 LCD. The power supply can drive the LCD using only three I/O lines, two of which are shared with other peripherals. The resolution of the internal ADC can be increased from 8 to 14 bits. Integer arithmetic is used to save computational power and ROM.

 

[Fragrance]

PIC-SUPPLY-1.pdf and PIC-SUPPLY-2.PDF uploaded in FM1/Mitsuko .
Total size about 750 Kbyte .

As usual no code available . You'll have to buy a preprogrammed pic at elektor .
Maybe you PIC geniusses can reverse engineer it ?
If you do , let us know .

Mitsuko

hi friend

please look at this topic the thing is already uplaoded in past

**broken link removed**

 

[meetmepal]

ATTN: Bagster - Microcontroller controlled power supply ....

dear friend (bagster),

i was just reading ur reply in the above said forum, i would greatly appriciate if you could send a copy of ur documentation of ur powersupply u had made, as i am playing around to make a power supply unit.

thanking you in anticipation

regards,
meetmepal

 

[coromonadalix]

HI
i have this project from : **broken link removed**

but as from today it is not available ... but i have saved all the files.

I whant to add a amp/hour fonction in it ... or have a 4x16 lcd instead of a 2x16, can some one give me some help how to do that ( calculations ) i whant to display it like this xx.xxxx if it's possible.

here's the original web site files ...

thanks

 

[lguancho]

**broken link removed**

An 80C31 controlled power supply. Can download pdf article and source code

 

[alphi]

0-25V/0-10A

 

[coromonadalix]

here's a new version
now it have a 8 amps limit

 

[hadihf]

Hi,
I contacted the author and he said this PS has noise at output which he could not eliminate so he removed it from his home page. Did anybody made this PS and had noise problem?

Regards

 

[ertug]

Like SMPS circuits the microcontroller may get all values from appropriate nodes and the software commands the switchs. :?

 

[alladinboy]

I found one construction in magazine Amaterske Radio 03/2007 + 04/2007 (more about this magazine at http://www.amaro.cz, but in czech language). Regulated supply 40V (50V), 7A (9A) with PIC MCU. I think, the construction is too expensive and I will make another one - with AVR CPU, cheaper and more scalable construction.

 

[necolei]

I am planning to build a microcontroller power supply. Should be symmetrical, 0-30V and adjustable current limit.. both voltage and current limit controlled via D/A converters.
Anyone out here who already did something like this, or has some suggestions ?

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Please don't reply unless you have useful information to add on this post.Thanks

Knowledge about Switch power supply will really help in doing such project.