ADWSystems
Member
I would like to design, or see if it is feasible to design, a module (eg., small PCB) I can reuse that will protect the inputs/outputs of a microcontroller or other logic level chip. I am work with many multi-voltage designs and would like to create, if possible, a module I can build multiple of to protect the logic circuits.
I am thinking the heart would be a CEL PS2501-4 optoisolator. It seems to have one of the highest CTRs, can handle a wide range of diode If (abs max 80mA with best CTR in the 5-10mA range), and an OK transistor Ic (50mA).
Here is what I have for design requirements:
1) Cheap
2) Small (size and component count)
3) Optically isolated
4) Reversible. I would like to be able to use the same board to protect the logic chip inputs as well as it's output by just turning the board around.
5) 4 channels on the board, matches the 4 optos available in the PS2501.
6) Diode input to handle at least 5V-12V inputs
6a) It would be even better if the input diode could accept at 3.3VDC
6b) It would be great if the input diode could handle 24VDC. I think this is a long shot without a clever idea. If diode resistor is 1k, then the power is just over 1/2W. That would be a lot of big resistors on a little PCB
I'm sure I missed some requirements that we will discover as we go along.
I am thinking the heart would be a CEL PS2501-4 optoisolator. It seems to have one of the highest CTRs, can handle a wide range of diode If (abs max 80mA with best CTR in the 5-10mA range), and an OK transistor Ic (50mA).
Here is what I have for design requirements:
1) Cheap
2) Small (size and component count)
3) Optically isolated
4) Reversible. I would like to be able to use the same board to protect the logic chip inputs as well as it's output by just turning the board around.
5) 4 channels on the board, matches the 4 optos available in the PS2501.
6) Diode input to handle at least 5V-12V inputs
6a) It would be even better if the input diode could accept at 3.3VDC
6b) It would be great if the input diode could handle 24VDC. I think this is a long shot without a clever idea. If diode resistor is 1k, then the power is just over 1/2W. That would be a lot of big resistors on a little PCB
I'm sure I missed some requirements that we will discover as we go along.