H-Bridge

[ChrisP58]

Hi,

Thanks for the replies.
If noise or small voltage leak is present at the output of the DC/DC convertor, will it effect the IC internal transformer, thus distorting the input of the DC/DC convertor?

Changes in the current drawn from the output of the converter, will affect the input current of the converter. What impact that has on the rest of the circuit will depend on what that circuit is, and how it is wired up.

 

[ikalogic]

The logic part. But since the ground is common for both the motor power and the logic, I was wondering if voltage leak to ground or any noise could cause any distortion at the input DC/DC convertor.

Why would you ever tie both grounds together?!! if you do so, then it's useless to galvanically isolate both supplies with such an expansive component!

If you use this DC/DC isolator, also use opto couplers to isolate logic command from the mosfet gates (or BJT bases).

 

[adrianvon]

Why would you ever tie both grounds together?!!

The H-bridge which I am using (BTS7960 ) have the motor and logic ground common internally, so there is no way that I can separate them.

 

[ikalogic]

Yes, but still, you can isolate the micro controller, USB, or what ever sensitive logic from the logic directly associated with the power part. This is exactly what i did for another project at work: I kept the motor, FETs and FET drivers on one supply, and all the sensitive logic and USB connection on another isolated supply. The signals coming from the MCU to the FET driver are opto-isolated. No any galvanic connection what so ever between MCU and Motor driver. If the motor generates tones of electrical noize, my circuit is still safe, not matter what.

 

[adrianvon]

Can someone please help me in selecting the resistors for the IS and SR pins with the BTS7960 ??

Any help will be appreciated.