Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Dual supply from single supply

Status
Not open for further replies.
Are you asking how this circuit works?

The output of the 555 is roughly form 0 to 12 volts. (slightly less)

The first cap "AC" couples the signal. The right side of the first cap has the same 12 volts peak to peak, but the DC is not the same. The diode going to ground keeps this signal from ever going more positive than 0.6 volts. So the voltage is -11.4 to +0.7.

The next diode and cap peak detect (rectify and filter) the signal. (in the negative direction) The -11.4 volts pull down on the output cap. There is another diode loss so -10.7 volts is about what you should get out.
 
So it's the AC coupling that does the trick, the diode limits the +ve V to 0.6V thus the making the relative amplitude - 11.4V
I guess schottky's would help efficiency.
 
Yes, schottky's are better than regular diodes, but synchronously switched mosfets are even better. I am using an LM2664 to make -3.3 from +3.3 with negligible voltage loss.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top