DC Voltage Doubler

Discussion in 'Electronic Basics' started by John, Aug 5, 2004.

1. JohnGuest

Hello

What's the best (easiest) way to double a 9V DC supply to 18V DC? The 9V
comes from a 78L09 regulator. The current requirements are very low. Do
any chips exist to do it? I'm an electronics novice so the simpler the
better.

Thanks.

2. John PopelishGuest

There are capacitor switches that charge one cap with the supply, then
connect it in series with the supply to double it. These need only a
couple capacitors to double (or make a negative of) a supply. The
base number for one such chip is 7660.

http://www.udl.es/usuaris/p7806757/0000-pdf/conversores cc cc/7660.PDF
http://www.linear.com/pdf/lt1044.pdf

3. Rich GriseGuest

Would it make more sense to supply the doubler with the same raw DC as
the 7909 is getting?

Thanks,
Rich

4. John PopelishGuest

The HT7660 is speced for an absolute maximum input of 13 volts, the
lt1044 for 9.5 volts, and the TC7660 for 10.5 volts. So, maybe, but
doubtful.

5. CFoley1064Guest

Subject: DC Voltage Doubler
If you need something right away, and the chips mentioned by other posts aren't
available, try a 555-based voltage doubler. If you use a 555, you'll need 2
more resistors, two extra diodes and one extra cap:

http://www.reconnsworld.com/power_voltdoubler.html

Good luck
Chris

6. ddwyerGuest

Generate a supply limited square wave, couple to a voltage doubler (3
diodes + 3 capacitors) sitting on top of the + supply . O/P = 9V + 2X9V
- volt drops minimised by using schottky diodes.
Regulate o/p down to 18V.