Did you read the datasheet for the mosfet ?If you read it I think you will find that you need -10V to turn it off.That's been your problem since the beginning. Only a logic level mosfet will turn off with 0V.Most require at least -7V to turn off. If you try connecting -10V to the mosfet gate I think you will find it turns off.The TC4427 is not a bipolar device so you would need one that runs off a +/- power supply voltage.The TC4427 has been a waste of time if you are trying to drive a mosfet that requires a negative voltage to turn off. Try turning off the mosfet with a 9V battery connected with the "+" to GND.'I don't know why the TC4427 won't turn off the led but I believe that is a different issue than why it won't turn off the mosfet.
post the datasheetRelative to the gate of course.
Pull up/down resistor are not needed if the pin is set to OUTPUT with pinMode.An Arduino pin has an internal mosfet switch to VCC and a mosfet switch to ground.Maybe your Arduino pin is damaged (assuming you did set the pin to OUTPUT).
The voltage relative to the gate would be -12V.I still think you should try connecting the "+" side of a 9V battery to the GND and "-" side to the gate
I looked at an old datasheet, and while it has min/max input values relative to VDD, it only lists a max VDD of 21VDC. All the characteristics are listed using a VDD of 18VDC.
Have you got your test circuit like this, and running the blink code with 3000 delay?
So, it's not clear why adding a pull down resistor would make a difference
2- When interfacing the TC4427 to an arduino, if the output won't turn off, first try the easiest solution, which is a pulldown resistor on the output of the ATMega328 (the TC4427 input)
QuoteWhen pin2 is connected to ground pin7 reads 0v.When pin2 is connected to Vdd(5v) pin7 reads 5v.When pin2 is connected to the arduino output pin then pin7 always reads 5v.
When pin2 is connected to ground pin7 reads 0v.When pin2 is connected to Vdd(5v) pin7 reads 5v.When pin2 is connected to the arduino output pin then pin7 always reads 5v.
Tried changing the arduino ouput pin and left out the pull down resistor and it works. Set the output back to pin 3 and the LED is stuck on. Put in another atmega328 chip and wrote the same sketch with the output on pin 3 and now its working. So there it is, an atmega chip with a bad pin.
Don't you mean, manually apply 5V to the input, then measure the output, then apply Gnd to the input, and again measure the output? Verify that it complies with the following table: