THVD8000: about THVD8000 connection

Hi Kiyoshi,

1. Nothing is wrong with the architecture shown in figure 1 - I'd still recommend a terminating resistance (120 Ohms) one on each side of the bus between A and B. If you are using a star configuration please refer to the point 2b below as this will require a slightly different/more complex system architecture.

2. The general setup is fine however there are a few caveats if it will work:

2a) This type of connection will reduce the max distance that the bus will be able to achieve - it is still dependent on other factors, but  since it is a single ended configuration the voltage sent along the wire will be reduced and in systems with large ground  potential differences there could be more glitches possible - this is going to increase with length and frequency of the system.

2b) Depending on how the connections are realized in the application i.e. the topology. Devices that are daisy chained together or there are junction boxes with short stubs connecting are preferred and this method is okay - if a star topology is used it will be more complicated than shown - please see this application note on star topology if this is the intended topology: https://www.ti.com/jp/lit/an/slla573/slla573.pdf?ts=1659626642381&ref_url=https%253A%252F%252Fwww.google.com%252F

2c) Terminating resistors between A and B are still recommended to help mitigate reflections - depending on topology chosen will dictate how many you need - in general we recommend 2, 1 at each end of the bus - but for star topology there are different considerations. 

2d) If you know the frequency you want to run at I can also check inductor/capacitor values. 

3. The configuration is correct as long as the MCU and power supply are on the same ground - but if the right power is going to the MCU the inductor and capacitor values need to be correct - if you let me know the design values I can check them for you. 

4. As far as the THVD8000 is concerned - yes this power supply is fine. If it will work with the devices that you are powering I would refer to its datasheet to check to see if they are compatible. As far as the THVD8000 part of the application is concerned its fine.

Fig 2. 

5. Yes there are a few problems - if a differential connection is used the power return path is connected to the "B" line via an inductor. So the inductor would go from "B" to the ground of the power supply.  So that means L4 is placed incorrectly it should be from "B" to power ground and any other node would have to have an inductor from B to power ground. The inductors are sized so that there is a minimum impedance between "B" and power ground. Also same advice as point 1 with the termination resistor except its between A and B. 

6. It could work in this configuration - but its not recommended please see above point for ideas how to fix this connection if this is the one that wants to be used.

7. If the component values are correct and the MCU uses the same ground as the power converter than yes it should - but please see point 5 for the correct implementation. 

8.Please see point 5 and 6. 

Please let me know if you have any other questions and I will see what I can do!

Best,

Parker Dodson