Design the loop Power 24V for current 4-20mA analog input

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Best Regards,,
J. Fullilove
Texas Instruments
TI Designs

Fullilove,

Thanks for the TI attention, i will wait for the answer.

Regards

Mansur. H

Hi Mansur,

sorry for the delay!

I assume you plan a 12ch 4-20mA analog input module with integrated power to power the field transmitters.

Some questions:

- Is the 24V (green box in your drawing) provided to the module from the field side (a 24V PSU is connected to isolated side of the module)?

- Do you need to control the power sources (able to turn on/off) of the channels individually (or global sufficient)?

- Do you want to limit the power of each channel (or global sufficient)?

- Are the 12ch channel-to-channel isolated or group isolated?

You may also be interested in this blog.

Thanks,

Lars

Hi Lars,

for the power supply is 24VDC inside the analog module, so, the analog input 2 wire already has 24V dc without external power supply.

control enable or disable is more advantage if possible, the maximum current for each channel is not  more 50 mA.

for 12 channerl we eant to design it for isolated and non isolated mode.

Regards

Mansur. H

Hi Mansur,

does it mean that the 24V are coming from the backplane side and are isolated? This means you have a isolated 24V*50mA*12 = 14.4W DC/DC PSU in the module...

For channel-to-channel isolated modules you would need to add an isolated DC/DC for each channel.

Maybe can can provide a drawing of the system power tree?

Have you seen the Analog Input End-Equipment Reference Diagram already?  

For per channel control I suggest to use a high-side switch such as TPS4H000-Q1 with Rdson=1Ohm @ 25C.

Thanks,
Lars

Hi Lars,
Sorry, we not use backplane, just controller and analog input (external ADC), my power supply is battery with 12 VDC. so we need step up to 24VDC.
For isolated i'm already understood with TI product.
For your TI article, i'm already done.

Thanks & Regards
Mansur. H