Simple Negative voltage converter

[shaikss]

Hi,

I want to generate negative voltage from the positive input of Low Drop Out Regulator.
How can I generate negative voltage?
My LDO output is in the range of 0.4V to 1V.
For my design, I need to convert the LDO's input to negative voltage to make sure that certain blocks are completely disabled.
I am using Cadence Virtuoso for simulations. Please help me

 

[FvM]

Using a charge pump similar to 7660?

 

[jpanhalt]

What is your positive input voltage? That may affect your choice of charge pump.

John