Power Supply for a ICL7135 +/- 5 volt power supply vs 5 power supply what is th

sam_sam_sam

In the three Panel Meter that I have they all are power with only a 5 volt power supply

Help me understand what the difference would be in easy to understand laymen term

Thanks for your help in this matter

This is the Project that I am working which power supply would better to use and why

Please explain in detail if you would

5 volt supply

or a

±5V supplies



Power Supplies

The ICL7135 is designed to work from ±5V supplies.

However, in selected applications no negative supply is

required. The conditions to use a single +5V supply are:



1. The input signal can be referenced to the center of the

common mode range of the converter.



2. The signal is less than ±1.5V.

See "differential input" for a discussion of the effects this will

have on the integrator swing without loss of linearity.







Differential Input

The input can accept differential voltages anywhere within the

common mode range of the input amplifier; or specifically from

0.5V below the positive supply to 1V above the negative

supply. In this range the system has a CMRR of 86dB typical.

However, since the integrator also swings with the common

mode voltage, care must be exercised to assure the integrator

output does not saturate. A worst case condition would be a

large positive common-mode voltage with a near full scale

negative differential input voltage. The negative input signal

drives the integrator positive when most of its swing has been

used up by the positive common mode voltage. For these

critical applications the integrator swing can be reduced to

less than the recommended 4V full scale swing with some

loss of accuracy. The integrator output can swing within 0.3V

of either supply without loss of linearity.



Differential Input

The input can accept differential voltages anywhere within the

common mode range of the input amplifier; or specifically from

0.5V below the positive supply to 1V above the negative

supply. In this range the system has a CMRR of 86dB typical.

However, since the integrator also swings with the common

mode voltage, care must be exercised to assure the integrator

output does not saturate. A worst case condition would be a

large positive common-mode voltage with a near full scale

negative differential input voltage. The negative input signal

drives the integrator positive when most of its swing has been

used up by the positive common mode voltage. For these

critical applications the integrator swing can be reduced to

less than the recommended 4V full scale swing with some

loss of accuracy. The integrator output can swing within 0.3V

of either supply without loss of linearity.

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··Thanks for any··that you may have and all of your time finding them

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Sam

Post Edited (sam_sam_sam) : 11/23/2009 1:21:07 AM GMT

Mike Green

I can't answer your question because it's too general. It's like asking about house paint ... Which is better, latex or oil-based? It depends on what you're trying to do and what your requirements are. How about if you explain what you understand?

sam_sam_sam

Here is the Project that I am working on

ICL7135 To a Prop Chip Feed back on board design Need Please Project in the works (Re-Named)

·I having hard time understanding what they are talking about


A worst case condition would be a

large positive common-mode voltage with a near full scale

negative differential input voltage. The negative input signal

drives the integrator positive when most of its swing has been

used up by the positive common mode voltage. For these

critical applications the integrator swing can be reduced to

less than the recommended 4V full scale swing with some

loss of accuracy. The integrator output can swing within 0.3V

of either supply without loss of linearity.


▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
··Thanks for any··that you may have and all of your time finding them

·
·
·
·
Sam

Post Edited (sam_sam_sam) : 11/23/2009 2:29:13 AM GMT

kwinn

Sam, basically you only need the -5V supply if you are measuring negative voltages. If you are measuring a positive voltage all the time the V- can be connected to the analog ground.