1.5v 'joule thief' pic micro power supply.

[dr pepper]

I've built a couple of torches using the joule thief idea and they work well.

Has anyone built a joule thief or similar to power a pic at a regulated +5, I need enough current to run the micro and maybe a couple of leds and a max232.

 

[edeca]

There are boost regulators which work from 1 AA battery, would they work? I have used one to power a PIC and an infrared LED. They are inexpensive and work well for the entire capacity of the battery. I would recommend you try and run the PIC and LEDs from 3.3v unless you really need 5v.

You can see the board I designed below, the LED is on the other side - it works great but don't expect a huge runtime unless you minimise current usage. The boost chip is an MCP1640 form Microchip.

View attachment 66027

 

[dr pepper]

Hadnt thought of using a proprietry chip.
Comments on 3.3 are valid, the only exception there though is the max232 needs 5.
I'm going to try just putting a 5.1v zener across a joule thief circuit rigged up on some breadboard, so long as theres enough inductance in the transformer might work.

 

[edeca]

What do you need the MAX232 for? Are you interfacing with RS232 or do you just want to talk to a PC?

If you just want a PC then look at the new FTDI USB chips, small footprint and powered by the computer.

 

[Mickster]

I stumbled upon this a few years ago:
**broken link removed**

Regards.

 

[dr pepper]

Great Mickster, I can use the pic to regulate its own voltage.

I could power the max232 from the rs232 port on the pc its connected to, the circuit is a data logger, however I'd like to power the whole thing from 1 battery.

Heres something I found ineteresting with google, one supply that works entirely on its own saving i/o pins and software, and another that self starts and can be controlled via software.

http://wiki.waggy.org/dokuwiki/electronics/joulethief#adjustable_microcontroller_power_supply

 

[Joe G]

I'm using a Voltage convertor to run my pic anamometer,I have it set for 3.3Volts, it runs w/ just 1 aa .
and they come in adj. or fixed versions up to 5volt

 

[dr pepper]

What device is that Joe?, and is it dil or smd?

 

[Joe G]

max 1722,1723 or 1724. these are the ones I am currently using. they are smd, variable or fixed Voltages, these supply up to 0.15A, I using them on a small solar project that is running at 3v and 27ma max. and it's been running for a couple of months now. Some of them supply up to 2 amps? I use them on led flashlites.