To build a dc-dc converter that can generate stabile negative output voltages you will have to use a transformer ..
Take a look at the attached circuit.
Although it was designed to convert +V to +V, by changing the polarity of assorted components at the secondary site you will be able to generate required negative voltage ie. +V to -V ..
The LM385 looks like an obsolete part, but it can be easily replaced by the LM431 shunt regulator ..
Hi ulaska
Use good electrolitc capacitor (low ESR) and use extra capacitors 0.1uF
(DISK or multilayer) parallel with output capacitor.
Or yo could use LC filter circuit in output,
with L=100-150uH and same capacitor.
Your suggested circuit is almost the one I am looking for a Positive to negative -12V, but need a little more current output to at least -1.2A.
- Is it possible that I can double the output current from -0.7A to -1.4A by connecting two output of Lm2576-12 together in this circuit?
-Or use other similar IC with higher current LM2677-12 with 5A step-down voltage regulator?.
I need to dc-dc convert and regulate from a 19.5V 3.34A ac to dc laptop adapter and need dual Pos & Neg +12V 1.2A, and -12V 1.2A Max supply for my power opamp opa564 circuit.