9 Volts to 12 Volts DC to DC converter

Discussion in 'General Electronics Chat' started by haran, Apr 12, 2008.

1. haran Thread Starter Active Member

Apr 6, 2008
42
0
i would like to know how to build a 9V to 12V dc to dc converter. I want to use a 9Volt battery as the voltage source(input).

2. hgmjr Retired Moderator

Jan 28, 2005
9,029
219
What is the power consumed by the 12V load?

hgmjr

3. mrmeval AAC Fanatic!

Jun 30, 2006
833
3
http://www.national.com/appinfo/power/

Plug in the values and it will spit out the part you need. I came up with the LM25575 but I can't find the specs on the power output of a 9v battery so don't know how much power it can produce.

4. SgtWookie Expert

Jul 17, 2007
22,201
1,809
9v PP3 "transistor" batteries are pretty low-power devices, perhaps 150mAh

If the load was more than a few mA, the battery would get sucked flat pretty quick.

5. haran Thread Starter Active Member

Apr 6, 2008
42
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how do i calculate the power load for a circuit?

6. Wendy Moderator

Mar 24, 2008
21,838
3,047
A X Hours = AH

What you need is a measurement of current your circuit requires from the 12V source, and we'll work from there.

7. haran Thread Starter Active Member

Apr 6, 2008
42
0
my circuit is using a 12 Volt input and the amp is below then 500mA

8. Audioguru Expert

Dec 20, 2007
11,249
1,349
If you make a voltage converter circuit that is 85% efficient and need 400mA at 12V then then 9V battery must supply 640mA.

A 9V alkaline battery's voltage drops quickly with such a heavy load. I have graphs from energizer.com and the highest current calculated is "only" 400mA.