Hi All
Let me say first that I havent used mosfets much before so all of my information is off the net
I have a 7 x 11 led array, each of the leds have a series resistor and the anodes of each column are commoned up as are the cathodes of each row.
In theory this will eventually give me addressable control of each led.
Because the rows and columns draw more than allowable current for the PIC micro that I am using (16F877A) I am switching the anodes only for now with IRF9630 p channel mosfets. All of the cathodes are simply commoned to the gnd rail for now.
I am using the micro to switch the gates of the p mosfets via a 800 ohm series resistor.
For the most part this is working but I have one row who's operation is inverted. I have hunted and hunted and cannot find what is causing it.
Have connected simple leds direct to the micro and it is working fine, have even swapped out the mosfet and still the problem remains. Any ideas?
All of the sources of these 7 9630's are connected together to a 5v power source and the drains are connected to the led columns.
Another thing I have noticed is that the mosfets seem to be switching on with a logic 0 from the micro rather than a logic 1, I will have to confirm this.
Thanks in advance for your help
Bruce
Let me say first that I havent used mosfets much before so all of my information is off the net
I have a 7 x 11 led array, each of the leds have a series resistor and the anodes of each column are commoned up as are the cathodes of each row.
In theory this will eventually give me addressable control of each led.
Because the rows and columns draw more than allowable current for the PIC micro that I am using (16F877A) I am switching the anodes only for now with IRF9630 p channel mosfets. All of the cathodes are simply commoned to the gnd rail for now.
I am using the micro to switch the gates of the p mosfets via a 800 ohm series resistor.
For the most part this is working but I have one row who's operation is inverted. I have hunted and hunted and cannot find what is causing it.
Have connected simple leds direct to the micro and it is working fine, have even swapped out the mosfet and still the problem remains. Any ideas?
All of the sources of these 7 9630's are connected together to a 5v power source and the drains are connected to the led columns.
Another thing I have noticed is that the mosfets seem to be switching on with a logic 0 from the micro rather than a logic 1, I will have to confirm this.
Thanks in advance for your help
Bruce