toohyetoreply
New Member
Hi,
I made a couple of posts on this already but I finally have a schematic drawn up. I'm just posting it here in case there's something wrong with it.
I'm trying to drive these LEDs with a microcontroller
**broken link removed**
Here is what I have come up with.
**broken link removed**
The microcontroller uses the select lines that top to select which digit will be turned on. Then it uses the a-dp lines to control which segment will be turned on. I'm using the mosfets as switches but I'm worried that they won't work as I want them to. There is 12 volts over the whole thing and the LED segments will take 11 volts of it, so there will be 1 V across the resistor and the 2 mosfets...*confused*
I'm also thinking of doing it like this:
**broken link removed**
And hooking it up directly to the MCU. The main thing i'm worried about this one is connecting the 12V to the MCU. To turn the LEDs off, the MCU will output 5V and there won't be enough voltage drop across the LEDs to light them, It will be like connecting to an open circuit so it shouldn't matter if there's 12V on the other side, right?
If the LEDs are on, the MCU will output 0V, but the LEDs will drop 11V, so there'll only be 1V connected to the resistor connected to the MCU pins, so I don't see how that can damage the MCU either. The only thing I have to worry about is the decimal points which won't drop 11V but probably around 3.7 volts, but then that would be dropped across the resistor anyways.
What do you guys think?
I made a couple of posts on this already but I finally have a schematic drawn up. I'm just posting it here in case there's something wrong with it.
I'm trying to drive these LEDs with a microcontroller
**broken link removed**
Here is what I have come up with.
**broken link removed**
The microcontroller uses the select lines that top to select which digit will be turned on. Then it uses the a-dp lines to control which segment will be turned on. I'm using the mosfets as switches but I'm worried that they won't work as I want them to. There is 12 volts over the whole thing and the LED segments will take 11 volts of it, so there will be 1 V across the resistor and the 2 mosfets...*confused*
I'm also thinking of doing it like this:
**broken link removed**
And hooking it up directly to the MCU. The main thing i'm worried about this one is connecting the 12V to the MCU. To turn the LEDs off, the MCU will output 5V and there won't be enough voltage drop across the LEDs to light them, It will be like connecting to an open circuit so it shouldn't matter if there's 12V on the other side, right?
If the LEDs are on, the MCU will output 0V, but the LEDs will drop 11V, so there'll only be 1V connected to the resistor connected to the MCU pins, so I don't see how that can damage the MCU either. The only thing I have to worry about is the decimal points which won't drop 11V but probably around 3.7 volts, but then that would be dropped across the resistor anyways.
What do you guys think?