regulate 12V down to -55V

Hello Zhen,

Welcome to the Forum!

With DC power supplies, the simplest way I can think of explaining it is that you can use the same chip, MOSFET, etc, to achieve a negative voltage output.  You can also use diodes and capacitors as well.  If you are familiar with switch mode power supplies and transformers then you will know that a negative component is created on the output side that can be used.  

It is more a technique than an actual device.  In fact, you can create an adjustable voltage regulator using an opamp and a precision 2.5V regulator.  There are resource available on the TI website for designing power supplies, you can search the site for more information.

The other point is that a negative voltage can be thought of as a positive voltage supply connected with the ground reference reversed.  If you have a dual output power supply, you can connect the outputs together and generate a full scale positive and full scale negative voltage from the unit.  You can search the web for how to connect up a dual power supply to generate negative voltages.

Depending on whether you just need something for doing a test or you need to supply these voltages for a stand alone device, will determine which of the above techniques to use.

Thanks,

Hi Zhen,

What output power do you need? That will mainly determine the type of power supply you need.

Or in Greenja's words: the technique you need.

The -55V draws maximum 30mA or 1.65W.  I would consider a efficiency of +65% to be effective.

The data sheet did not specify the tolerance of this supply.
It only states:
"VSUB(-55V) must be the most negative potential of the IC."
and also the ABSOLUTE MAXIMUM RATINGS says that It can not go beyond −60V.

As you can see, the power requirement is not big.  I hope i can find a chip that allow me to go down to -55 easily.

Also , i hope I can avoid the use of transformer, and reply solely on inductor.(but not necessarily)

.Since i am a first year engineering student,  I do not have the ability to "design the wheel" or implement some high level design.

So that is why i am simply  looking for a chip to help me get there.