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Regarding supplies for isolated amplifiers

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Advanced Member level 1
Jan 28, 2011
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Hi all,
I am designing a sensing board for sensing voltage( DC-link ) and Outpu voltage , current (high side). As we need to use an isolated amplifier like ACPL-C79A. Now for each sensing, i will be requiring an isolated supply for input for the amplifier. What is the best practice in this case? Is it to make auxiliary power supply (with a number of isolated outputs) or to use board mounts isolated dc-dc converters for each required isolated output


It's not clear to me what exactly you need.
When you talk about an isolated supply, then I expect informations like:
* input voltage (range)
* isolation voltage
* output1 voltage
* output1 current
* (voltage and current for other outputs)
* total power

Then I'd go to a distributor or DCDC converter manufacturer and look for matching devices.

For sure you are free to design your own DCDC converter.
This is a question of: effort, cost, volume, electrical parameters (like drift and noise...), other ideas
We can't answer questions about effort, cost ...

So I'd rather like to ask you where you see the benefit in designing your own.
Or the other way round: When you see the ready to buy DCDC converters, what don't you like on them?


Just for clarifications.
In commercial inverter let say. There are requirements for isolated drivers, sensing circuits, and microcontrollers. What is the general method to supply voltage to these systems?
Is it making a multi-output offline converter (15V, 5 V, 3.3 V, with isolation as required)?
Or Using a standard available offline converter of say 15 V. And use other dc-dc converters for requirements of (isolated 5V,3.3 V, etc).

Isolation working voltage, clearance, creepage and test voltage according to safety standards are important criteria, also EMC condsiderations. These days, DCDC modules at point of load are often preferred.

In commercial inverters, the auxiliary power supply is often derived from the DC bus.

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