Producing negative voltage (-12 Volt) from 12 Volt

[Bluestar88]

Hi guys, I want to produce -12 volt for power of Op-amps in my circuit. For this purpose, I have a power supply +12 volt and I am going to convert it to -12 volt...I did a lot of search about this subject and I found MC34063 for produce negative voltage.... In its datasheet there is a circuit to do it ( I placed it in picture below)..but in this picture input is between 4.5 to 6 volt...but I have 12 volt..I do not know how I can use from this IC? please help me...

 

[crutschow]

The data sheet says it can be used with inputs up to 40V so you should be able to use it with 12V input. But you need to select the components per the last column in the Figure 17 Table in the data sheet by using 12V for Vin and Vout.

 

[Bluestar88]

I used the below link: **broken link removed** about MC34063 for producing -12 volt from 12 volt (Frequency 0Hz).....I have a problem about it..Is it inappropriate for this purpose? I am really eager to visit an sample circuit with this IC...Please help me...

 

[crutschow]

You just need to input the operational parameters for the circuit into the program and it will give you the circuit values.
You want to keep the frequency below the 100kHz limit of the device.
You can round off the component values to the nearest standard available.
What is your problem?