# Voltage regulating help

#### codemastercool

Joined Jan 23, 2012
9
Hello everyone,

I'm currently working on a small project for one of my engineering subjects. What we have is a mechanism that works at 3-4 voltage levels, depending on how we want to manipulate it.
What I'm thinking of is trying to design a circuit that takes in an input voltage, but at distinct time intervals will increase that voltage going into the mechanisms' inputs. Is this possible?

For example, if my operating voltages are 2, 5, and 8 volts, will it be possible to design the circuit so that it regulates to these exact levels?

Thanks in advance, I really appreciate it.

*EDIT*

Also to be noted is that this is for a project that works with wafers, and we have to fabricate the whole system on a chip.

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#### bountyhunter

Joined Sep 7, 2009
2,512
What is your input voltage source? What output voltages and currents are needed?

It's relatively easy to build a voltage regulator that cn step between different regulated output voltages.

#### PaulEE

Joined Dec 23, 2011
423
What is your input voltage source? What output voltages and currents are needed?

It's relatively easy to build a voltage regulator that cn step between different regulated output voltages.
One possible configuration would involve an LM317 regulator and adjustable feedback resistors; say, with an electronic switch. Take a look at the LM317 voltage regulator, the method of resistive feedback to "set" the output voltage, and the CD4066/74HC4066 quad bilateral switches. You can toggle the switches on/off with a digital logic input from switches, uC, etc.

#### codemastercool

Joined Jan 23, 2012
9
One possible configuration would involve an LM317 regulator and adjustable feedback resistors; say, with an electronic switch. Take a look at the LM317 voltage regulator, the method of resistive feedback to "set" the output voltage, and the CD4066/74HC4066 quad bilateral switches. You can toggle the switches on/off with a digital logic input from switches, uC, etc.
In this case, some sort of control would have to be done manually, yes? As in, I would have to physically adjust some switch or so?
I'm trying to make this completely self-operating - the only controls I plan to have are a set (which would set the mechanism working), and a reset (bringing it back to the starting voltage).

#### mcgyvr

Joined Oct 15, 2009
5,394
Need more information.. Exactly what voltage/current levels do you need, when do you need them..what is this thing doing,etc... much more detailed information is needed..

If you want it all automatic I'm sure it can be done that way.. But we have no idea what you are actually trying to do.

It could be as simple as having a single supply split into the voltages you need via regulators and simply turning on relays or whatever when you want power these unspecified devices.

#### codemastercool

Joined Jan 23, 2012
9
I'm sorry for being a little paranoid with respect to the information I've provided. Let me start from the beginning.

I'm working on an Integrated Microsystems project, involving a circuit and a MEMS device. I'm a circuits student, and the circuit that I would like to design will have the following features:

* The input is not set yet, however we will be using a DC input.
* Desired output ranges from 2V to 9V, although we will mostly be limiting the usage to around 6/7V.

* This output voltage will aid in the movement of the MEMS device. We have 2 moving parts (let's call them X and Y). The way I desire for it work is like this - X cannot move while Y is stationary. Y will have only one kind of movement, but X here is the main part of the MEMS structure, and it is designed to have large vertical movement. This vertical movement will depend on the voltage output of the circuit.

* Another desired idea - I want to adjust the output of the circuit in such a way that with distinct intervals of time, the voltage output increases (within the range, of course). So something like:
Vout = 2V -> wait for 2 seconds -> 3V -> 2 more seconds -> 4V -> and so on.

* While this is going on, arm Y also receives a voltage, HOWEVER, Y's movement does not require a varying magnitude of voltage, because we are not varying the degree of Y's movement. So assuming it worked on say, 1V, every 2 seconds Y would receive a signal of 1V (in synchronicity with the increasing signals going to X).

I hope this makes the question much clearer. I'm sorry, I'm just a little paranoid about divulging details

#### crutschow

Joined Mar 14, 2008
27,023
You could use an LM317 (provided its current capacity meets your needs) with different resistors as PaullEE suggested. This could be sequenced by a 555, connected as an astable multivibrator, which drives a counter (such as a 4017) that controls the switches (such as a 4066) selecting the desired voltage controlling resistor.

Are you familiar with digital counters and analog switches?

#### BillB3857

Joined Feb 28, 2009
2,543
Or a DAC (Digital to Analog Converter) fed from a counter and followed by a scaling amp.

#### codemastercool

Joined Jan 23, 2012
9
You could use an LM317 (provided its current capacity meets your needs) with different resistors as PaullEE suggested. This could be sequenced by a 555, connected as an astable multivibrator, which drives a counter (such as a 4017) that controls the switches (such as a 4066) selecting the desired voltage controlling resistor.

Are you familiar with digital counters and analog switches?
Thanks so much! And yes, I am familiar with digital counters and analog switches, although I'll admit I'm not too good with analog design. (heh heh)

Or a DAC (Digital to Analog Converter) fed from a counter and followed by a scaling amp.
I haven't come across a scaling amp yet, could you give me some more details about that please?

#### BillB3857

Joined Feb 28, 2009
2,543
A scaling amp is, in basic terms, an amplifier with a gain set to provide the range of output voltage desired when the output from the DAC does not meet the need directly. Usually, it is an operational amplifier.