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Smart Power Switches Forum Discussions

User21985
Level 1
First question asked
Level 1
Hey,

I've a question regarding the use of isolated drivers with BTS50085-1TMA. The datasheet says that there are two grounds in smart MOS application, namely "Logic GND" and "Load GND".

1) How would my circuit be affected if logic and load gnds are shorted via a "net tie" or "0 ohms" ? Does it affect the current sense accuracy?
2) Does BTS50085-1TMA isolate load and logic side with an internal isolator?

Healthy days,
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1 Solution
Pablo_EG
Moderator
Moderator 250 sign-ins 250 replies posted 25 likes received
Moderator
Hello Akifadas,

Thank you for your question.

BTS50085-1TMA can be used with isolated drivers, this is the main reason why there are two GNDs shown in the datasheet.
1) Logic and Load GND can be connected, as seen on page 10 of the datasheet.
However, I would recommend using an isolated driver or connecting Logic GND directly to the GND of your board, not between Load GND and the board's GND.
I attach an image as a reference. This is to avoid having Logic GND shift voltage level due to the ΔV caused by the load current.
5177.attach

2)As shown in the datasheet's block diagram, the device does not have an integrated isolator.

Let me know if you have further questions.
Have a nice day,

Pablo

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Pablo_EG
Moderator
Moderator 250 sign-ins 250 replies posted 25 likes received
Moderator
Hello Akifadas,

Thank you for your question.

BTS50085-1TMA can be used with isolated drivers, this is the main reason why there are two GNDs shown in the datasheet.
1) Logic and Load GND can be connected, as seen on page 10 of the datasheet.
However, I would recommend using an isolated driver or connecting Logic GND directly to the GND of your board, not between Load GND and the board's GND.
I attach an image as a reference. This is to avoid having Logic GND shift voltage level due to the ΔV caused by the load current.
5177.attach

2)As shown in the datasheet's block diagram, the device does not have an integrated isolator.

Let me know if you have further questions.
Have a nice day,

Pablo
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