Part Number: TIDA-01590
We are looking for the current sense measurement solution for solar plants where voltage string is carry 1500V up to 30A.
This TIDA-01590 reference design seems like possible solution, but it is limited to the 1200V, as it says in its title "Reference Design for 1200-V, Isolated, I2C, High-SideCurrent Sensing for Solar Combiner Boxes".
What should be changed so that this reference design can be used for 1500V 30A?
We are thinking about design of new PCB based on this reference design. It should measure 16 strings, so we will need some I2C mux for 16 channel, so possible we will use 2x PCA9548A with diff adresses.
Thanks for using the E2E forums! The board as designed is configured for a 1200V, 15A setup. The limiting factors for this are the following:
- for the voltage, the DC/DC transformer was selected with clearance for 1200 V. If you want to step up to 1500V, you will need to select a new transformer that can handle this:
- The current rating is limited by the current shunt amplifier selection. The INA260 implements an integrated shunt resistor that is rated for 15A. Measurements above this current rating are able to be made, but potential damage can be caused to the device if allowed exposure over a certain time:
You can increase the current range by selecting an external resistor setup that will allow for better thermal dissipation outside the package. If you wish to maintain the digital nature of the part, I would recommend looking at the new INA229
Carolus Andrews, Analog Applications, Current and Hall Effect Sensors
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In reply to Carolus Andrews:
Thank you for your answer. INA229 with external shunt should solve problem of current.
Do you have suggestion for the transformer which can withstand 1.5kV? I know this is not from your portfolio, but it would help me a lot, if you already used some in some other designs.
In reply to Dragan Belgrade:
I've heard back from the systems team here, and they've said a majority of this will be in your court, as it comes down to the specifications you are trying to meet for your or your customer's needs.
At the 1.5kV level, increased creepage and clearance are usually needed to meet certain safety standards. We placed a slot in the board to meet the creepage spec, but the clearance was limited by the transformer.
The push-pull transformer used on this design is one of Wurth’s catalog parts that is designed to be used with the SN6505. We chose this part as it was the best option that was off the shelf available. To go beyond this, it would seem a custom coil would needed, which you could dictate the parameters of for your design.
If you can define your needed isolation requirements, we may be able to assist further. With this information, we can determine what transformer is needed for the isolated bias supply, and there should be no need to change the SN6505.
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