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How to generate the negative voltage

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mitgrace

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generate negative voltage with positive input

Dear All :
My design is input is 2.3v , then I want to generate the +3 ,and -3v .
we want to using charge pump method, Does anyone have any ideal or experiment ? Thanks
 

pakitos

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charge pump to generate negative voltage

you can not take from the same supply positive and negative voltages !!!!!!
can the input be 2.3 from two seperate supplies?
give more details from where the input is taken?
 

FvM

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generate negative dc voltage

you can not take from the same supply positive and negative voltages !!!!!!
Of course you can, charge pump is an option. Any RS232 driver IC shows how to. Apart from simple inverting/noninverting voltage doublers, there are e.g. multi capacitor factor 1.5 multipliers. But I don't deal with IC design.
 

PaloAlto

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negative on top voltage is negative

Are you talking system or IC design?
 

pakitos

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negative voltage booster

FvM said:
you can not take from the same supply positive and negative voltages !!!!!!
Of course you can, charge pump is an option.

What I mean let us say you have a battery with + and -
to get +V you take signal at + and ground as -
you can't take for the same battery - as signal to get -V and + as ground


charge pump is something else since the reference is fixed you are just inverting the signal's voltage

Hope I am clear
 

FvM

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how do you generate a negative voltage?

Yes, but the question was exactly about designing a charge pump. Charge pumps also involve voltage scaling or "transformation" by fractional ratios, not just inversion. In my view however, inversion is a way to took a negative voltage from a positive supply.

As the question was placed under IC design, I assume that it's also meant this way. Thus detail implementation is not my business.
 

mitgrace

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what is negative voltage

Dear pakitos:
Thanks the paper, Becasue I still study our system specific. I will work in IC design. Do you even work on DC/DC ( boost) , The voltage is 2.3v input, the output is +16 / -16 output. we just can use one inductor,any comment. Thanks
 

pakitos

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negative voltage ic

please can you rephrase your question?
you want to design a circuit which amplifies the dc voltage from 2.3 V to +16 and -16?
using only 1 inductor?
 

mitgrace

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positive to negative voltage ic

Dear Sir :
Yes , This is another questions, If we don't use charge pump. We want to use DC/DC boost circuit.
theat generate +16/ -16 , and one inductor, How do we implement ? We see other company finish it , and the bomb, it just use one inductor. So that we are very confused, How to implement it ? Thanks
 

FvM

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negative voltage boost ic

Did you fix your specification now? If so, you may want to mention a few more key parameters, e.g. intended regulation accuracy, input voltage range, current level, acceptable external component count.

Generally, a "one-inductor" design should be possible, but most likely at the expense of other external components as additional capacitors. You're talking of a single inductor, not a transformer?
 

mitgrace

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negative voltage

Dear FvM :
Actually , the detail specific is not final. But we have seen other product do that ? We don't know how is the performace and any issue when you use one inductor. The product is apply in Driver IC ( alike TFT-LCD). DO u have any comments , Thanks
 

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