Infineon BTS 6143 current sensing and a question about interferences

Hi everyone,

these may seem like beginner questions, but please bear with me because I am a true beginner.

I am trying to use this component with Arduino Mega:

Am I correct in assuming that the sense pin on this component should be connected to an analog pin on Arduino?

Another question that is bothering me as well: Arduino Mega will control the power for several devices using these components above. The devices are Intel NUC PC, several PWM heaters (low number of Hz, nothing high frequency), CCD camera, a separate device with stepper motors. All that draws power from one PCB with common GND. I want to avoid possible interferances and put some capacitors and resistors at the output. I may or may not actually use them, depending of whether the interferances are present or not (CCD camera is the most important in this case).

What values should I use? There are eight outputs that should not exceed 5 A at 12 V under normal conditions. I would use a switching power supply.

Thank you so much for your valuable input,

Miloš

To start with you chose a great part. The sense pin is a current mirror that outputs a current in relation to the current that is being drawn by your load. You do not need to connect the sense pin. Caution since it is a current source its output it can almost reach Vbb which is the supply voltage for your load. You can start with a resistor in the 1K range connected to the sense pin and ground to determine where it is going to go. Then I would suggest if you connect it to an analog pin you put a 10K or larger resistor between the Sense pin and the analog input with the 1K or whatever resistor also connected to the sense pin and ground. This will help protect the arduino against any transients.
Good Luck & Have Fun!

Thank you so much for the advice, I’ll test that!

gilshultz:
To start with you chose a great part. The sense pin is a current mirror that outputs a current in relation to the current that is being drawn by your load. You do not need to connect the sense pin. Caution since it is a current source its output it can almost reach Vbb which is the supply voltage for your load. You can start with a resistor in the 1K range connected to the sense pin and ground to determine where it is going to go. Then I would suggest if you connect it to an analog pin you put a 10K or larger resistor between the Sense pin and the analog input with the 1K or whatever resistor also connected to the sense pin and ground. This will help protect the arduino against any transients.
Good Luck & Have Fun!

I am now sure if I chose a great part. I can't seem to get it to work. The IN pin, which has to be shorted to GND, ouputs 11.5V when not shorted and when the Vbb is connect to the power supply (12V). That is very strange. Also, when the IN pin is not shorted to the ground, the output pins provide 11.5V, and when I connec the IN pin to the ground to switch it on, the output pins provide 12V. I tested several pieces of this component. No shorts, corretly wired.

The IN pin, which has to be shorted to GND, ouputs 11.5V when not shorted and when the Vbb is connect to the power supply (12V).

Yes, that is called "low side switching", you need an NPN transistor between IN pin and GND, switched by the Arduino.

Also, when the IN pin is not shorted to the ground, the output pins provide 11.5V, and when I connec the IN pin to the ground to switch it on, the output pins provide 12V.

Did you have a load connected between output pins 1&5 and GND?

The IN pin is an input to an ordinary grounded switch. The BTS6143D is not directly Arduino compatible.

IN cannot be connected directly to an Arduino output, because of the voltage mismatch problem. To use this with Arduino, you need an additional transistor (bipolar or MOSFET), with appropriate gate/base resistors.

Pololu has a good selection of high side switches that can safely be used with Arduino, and don't require extra components.

Thanks for the answers guys. I should have written that I used a BC847A transistor for switching. Even with the transistor, the output pins gave around 11.5V when not connected to the load. Maybe that is the problem – the load has to be connected. But, since this is a device that has multiple outputs, not all outputs outputs will be used all the time. Is it safe to leave some outputs without a load? How should I continue with the development?

Why do you think this is a problem?

If you want help with a circuit, post the complete circuit diagram. Hand drawn is fine. Image posting guide

Yes, you are right, it's best to post the circuit.

This is the part of the circuit with BTS6143.

IN5 and FB5 are connected to digital pins on Arduino. FB5 is intended for current sensing. The transistor is BC847A.

Maybe the real problem is that I am unable to find all the information in the data sheet (maybe the information is there, but I simply do not understand it).

So, this is what bothers me in understanding this component: the IN pin activates the switch when shorted to the GND. What amount of current flows through that connection when it is connected to GND?

The other thing is, is it possible not to have a load connected to the output pin and why does the output pin provide voltage when the switch is not activated (the IN pin is not connected to GND)? What amount of current is provided on the output pin when the switch is not activated? Perhaps all this information is available in the data sheet and I would be grateful if you could explain this to me.

Miloš

Please post a circuit diagram with component types and values.

why does the output pin provide voltage when the switch is not activated (the IN pin is not connected to GND)?

Most likely, you are measuring irrelevant leakage using a multimeter with 10 Meg input impedance. Put a 1K load resistor from output to ground, and see if there is a relevant voltage across it, with IN unconnected.

I think you might be right about that leakage. I'll test that out.