need variable DC voltage

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pasicr

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Hi for all,
I need variable DC voltage from +2VDC to -2VDC,
change continuously with 0,1 VDC step,
for example,
on two connectors,
one on negative potential the other start with +2VDC, after 30 seconds that point need to be +1,9VDC, after 30 seconds need to be +1,8VDC.........
and when come to 0VDC, then continue with negative -0,1VDC, after 30 seconds -0,2VDC....until reach -2VDC

can somebody advice what will be the best method to reach that?
thanks
regards
 

You have not mentioned whether it is a voltage reference or power supply?

In other words, what are the current requirements, a few uA, a few mA or a few Amps?

Do you have any experience with microcontrollers, if so and you are seeking a voltage reference, a few uA or mA, then a Bipolar DAC might be an option.


BigDog
 
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    pasicr

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Hi,

If you don't have negative supply voltage you may generate it with a charge pump.

I'd use a tiny microcontroller with a pwm output.
Use a spdt analog switch to change between +Vcc and -Vcc.
Control the switch (duty cycle) with the pwm output.
An RCRC filter generates DC voltage ...

Klaus
 
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    pasicr

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Another option, there are a few dual supply digital pots available which could then be followed by a opamp in a voltage follower (unity gain buffer) configuration to prevent loading.


BigDog
 
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    pasicr

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Thanks for replay,
Need to be power supply with few mA,
exactly I need power for electrodes in galvanization process,
 

Hi KlausST,
thanks for your reply,
can you please send more info about spdt analog switch use?
I have MAX394 spdt analog switch,
thanks in advance
regards
 

Hi,

What's not clear?
NC to -Vcc, NO to +Vcc.

Klaus
 
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    pasicr

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