Smart Power Switches Forum Discussions

[User20054]

Hello,

I want to use BS50010E and BS50025D smart high-side power switches instead of relays for power distributon in Formula Student Race Car. Is it possible to turn mosfet ON (PIN2, INPUT) with same signal from Battery supply (12V)? This is schematic of our board and MOSFET pinout :

[User20054]

After connecting 12V INPUT I have voltage drop to 7.2V at the output... same thing when I connect 12V to voltage 3.3V/5V drop-down regulator and 4.7kOhm resistor to INPUT, also voltage drop to 7.2 V at output.

[User270]

The table Absolute Maximum Ratings for Vin shows Vinmax= VS, so it should be possible to turn the output MosFET on with VIN=VS. For correct output voltage measurement a load must be connected to the output.

[User20054]

@forix, thanks for the response. What is the minimum load for these mosfets to turn ON? After connecting fans to BS50025D and ground (PIN 1) to battery ground, sometimes it turns on sometimes it doesn't. Every time i connect ground i either hear click on fan or it turns ON, so mosfet is doing somethig but I don't know what can cause this behaviour.

[Abhilash_P · Accepted solution]

Hi,

As per the explanation provided, the pin Vin of the MOSFET is a digital state pin and is used to control the state of the MOSFET. The pin 4 has to be connected to the battery voltage.
Since the battery voltage is constant, connecting pin 2 to the output of a battery does not help us in controlling the state of the MOSFET.
Can I please know how do you achieve this?

And also as forix mentioned, for measuring the output voltage, a suitable load has to connected. Ans since the load is a fan, which is a non linear load, I suggest you to connect a fwd across it.

Regards,
Abhilash P