+15V and -15V Power Supply

Hi guys.. I need help from you all profesional designer..
do u have any design of a power supply..

I have a 24VDC input adapter and i need to get a +15Volt and -15Volt to become my Vcc and Vss of my circuit. I have also LM7815 and LM7915. How am i going to get the +15VDC and -15VDC from a single +24VDC supply?

Please include me a schematic circuit diagram for reference.. thanks =)

+15V can be directly stepped-down from 24V with 7815 voltage regulator, then you can use 555-based negative voltage generator to generate -15V ..
But ..
Many (if not all) circuits will happily work of +/-12V instead of +/-15V ..
So, you can easily divide 24V into two halves by generating virtual ground, and attached is an example of such a circuit ..
More at:
Virtual Ground Circuits

IanP
:wink:

Can you give the output current requirements.
you could use a dc-dc converter, LT3579 for high output current. Again, you could use different one, a power suppy spec is incomplete with current requirements.

The max output current can be 1A.. any simplest way just using the 7815 and 7915 regulators with a single 24VDC source to get the +15V and -15V?

syee10 said:

The max output current can be 1A.. any simplest way just using the 7815 and 7915 regulators with a single 24VDC source to get the +15V and -15V?

Click to expand...

You can't get there using your given parts.

abs(15)+abs(-15) = a 30 volt difference. Your source can only create a 24V potential difference. Linear regulators (the 7815 & 7915) can only reduce the magnitude of the voltage... e.g. a +15V regulator needs more than +15V to create a stable 15V output, say 17V or more. Similarly, a negative linear regulator can only reduce the magnitude of a negative voltage, so to create -15V, you need -17V or more. In order to create your +15/-15 rails, you'd need something closer to a 36V supply (36/2 = +/-18, which can be linearly-regulated down to +/-15V nicely).

If you are stuck using the 24V source, and can implement your circuit such that +/-12V rails are sufficient, then using the virtual ground circuit that IanP mentioned would work. Just be sure that you don't connect your virtual ground (24/2 = 12V) to TRUE ground.

If you could drive the system from an AC source, then you could use a center-tapped transformer to generate a + and - AC voltage, then rectify them to + and - DC voltages (two full-bridge rectifiers, one +, one -).

There are many options, it just comes down to what trade-offs you can work with.