Analog to Digital for costom IC

[Dragon Tamer]

This may seem like a really stupid thing to ask, but I just can't seem to figure out how to get this to work. What I'm trying to do is take a comparator for a circuit that I later intend to make into an IC for myself and for sale. I have several problems that I can't seem to workout.

The way I want the IC to work is that there are 3 voltage supplies, one for the chip, one for the first input and another for the second input. That's the analog part. The voltage supplies for input 1 and 2 are for an internal reference for the comparator. There is an input pin that will either be connected to Vcc or ground to establish whether the inputs are a sinking or sourcing input (one for each). I can't seem to get the source/sink control pins internal circuit to work properly. I'm trying to use simple logic gates to power transistors for the comparator (because the actual input is still analog). I want the output of the comparator to be high when the input is respective to the source/sink control pin. IE: s/s High, input high, comparator output high, and s/s low, input low comparator output high.

My second problem is that I want the IC to drive both common anode and common cathode LED's. This is the part that has given me the most trouble. I want the output of the comparator to drive transistors or logic gates, something. There is a Common Anode Common cathode pin that will switch the outputs to their opposite state respectively.

Any help with this is greatly appreciated. I don't care what the inputs are, all I want is for simple logic gates only to be used.

PS: there are 3 outputs and 2 inputs

 

[Roff]

Your description is incomprehensible to me. What do you mean, "sinking or sourcing input"? Most comparators (analog, anyway) have high impedance inputs, with negligible input current.
Perhaps a block diagram would help.

 

[Mikebits]

Your description is incomprehensible to me.

I thought it was just me. As an aside, last I heard fabricating your own IC cost several hundred thousand dollars, so I am assuming a mixed signal FPGA of sorts. **broken link removed**

 

[Dragon Tamer]

It doesn't mater if the comparitor has a low current output, because that's where the analog stops. The comparator simply drives the logic gates. Correct me if I'm wrong, but doesn't an FPGA require a programing backround? FYI the cost to make the chip isn't much of a concern, I intend to secure a patent (still expensive though) then sell the rights to make the chip (whatever the process is called) to one of the larger companies to make some profit (any profit would be nice at this point). And yes, I can provide a block diagram, but I need time to make it.

 

[Roff]

It doesn't mater if the comparitor has a low current output, because that's where the analog stops.

In your first post you were talking about INPUT sourcing/sinking. That's what I was questioning.

 

[blueroomelectronics]

Lots of microcontrollers have built in comparators. What would your chip offer that was different / patentable.

PS personal patents are worthless. Google Don Lancaster.

 

[Dragon Tamer]

My IC only needs 14 pins, should be able to opperate off of 30V, and requires absolutely no programing. All it is intended to dois drive a full color LED, or 3 LED's based on 2 inputs.

 

[blueroomelectronics]

Any market for this? Why would anyone want one?

 

[Dragon Tamer]

I got the idea from working with a MAX712 and an ICL7665. I'm just improving on the idea a little. Here are the schematics of what I came up with before. I didn't really know what to call them before, for now I'm calling them "LED encoders." Any other better names will be accepted. The third pic is of the desired block diagram. I understand that some of the features are complex, they can be skipped.

 

[Hero999]

Sorry, but I fail to see why I'd need that?

If I wanted to do it, I'd just build it using an LM324 rather than buying a more expensive proprietary IC. I would also add some feedback resistors to introduce hysteresis.

 

[Dragon Tamer]

That's what I did, I'm just looking to make it a little... smarter. I did add a few simple extra's so that it can work with a micro controller. However there is one thing that bothers me (besides what I originally posted) I can't find a constant current source for the internal circuit (I have the one for common cathode but not common anode).

 

[Roff]

I'll ask you again - WTF is this input source/sink stuff?

 

[Dragon Tamer]

It determines whether the input is supposed to sink or source current.

 

[Roff]

It determines whether the input is supposed to sink or source current.

Comparators don't source or sink current at the input. Are you talking about the output?

 

[blueroomelectronics]

I suggest you read up on comparators before embarking on making a custom IC. Try building it in a simulator first. Also why 30V why not a lower voltage?

 

[Dragon Tamer]

I know about comparitors, I'm talking about the input of the IC being connectd to ether a pull up or pull down resistor for the sinking or sourcing input. I was going to do it in a sumulator, but I needed to wait until now to gain access to the simulator, The reson for the High input voltage is so that the IC can work with just about any other external part.

 

[blueroomelectronics]

You can download the free LTSPICE or trial Electronics Workbench (I forget what it's called now) And... What is the purpose of this IC (IE who / what would need it)

 

[Dragon Tamer]

I'm only making the IC because of 2 reasons,
1) I'm bored
2) I thought that it was a good idea

I have figured out the entire circuit except for the constant current source for the common cathode LED, I already have one for the common anodode LED. Please help me out with this minor detail.