MC34063 Buck Boost

[barry wilkins]

Hi I have trying to make a power supply to give me outputs
Say +10 volts & -10volts from 12 volts.
I have some MC34063 ICs so am using them ,but the circuits do not work ?
Even the one on the application notes from thr MFR
The osc. is working I can see that on my scope ,but the output say pin1 is wrong to me .?

barry

[eccerr0r]

Re: MC34063 Buck Boost

Dead IC? Misconnected IC?

Have a photograph of your setup?

[stj]

Re: MC34063 Buck Boost

there are chinese modules that will give you +-12v from a single supply - people use them to drive audio pre-amps.
you could use that followed by LDO linear regulators to get it rock stable - or just mod one for +-10v

if you make your own, remember it's high frequency.
schottky diodes only and low esr caps or it will fail

[redwire]

Re: MC34063 Buck Boost

Look for "1W DC-DC" and you can find the smaller SIP modules. There are bigger 2-3W ones as well. They are not regulated and have a min/max load. Mornsun seems to be the low cost ones, B1212S 10.8V-13.2V in, and 8% variation with the 12V output.
There are dual +/-12V or +/-15V modules too.
It's just much less hassle in a project to use these instead of making one.

[eccerr0r]

Re: MC34063 Buck Boost

I found the MC34063 fairly easy to use ... though as said, part selection is critical.
I had a small variable 1A PSU based on the MC34063 but eventually took it apart as the components I had on hand could not regulate across the whole band I wanted.

I eventually repurposed it to a 5A converter to reduce the voltage of my solar panel, seems to work okay... used an external 2n3055 + PNP as complementary darlington pair as the switch. Not a very good switch, but works good enough.