IRL520 Symbol in Express SCH - Being driven with BS2

Photon Artist

I am trying to create a schematic in the newst version of Express SCH.
What symbol should I use for the IRL520?· · Thanks

Rus

CanYouC3D

Check out this wed page http://www.irf.com/product-info/datasheets/data/irl520.pdf to see.

KenM

You could use a generic N channel FET, or get fancy and create a custom component, which I have done and uploaded to this forum.

There is also a picture of the component shown below. I believe you will need to save it to your express pcb "SchComponents_Library" folder. At least that is where it lives on my system after creating and saving the custom component.

Ken

Photon Artist said...
I am trying to create a schematic in the newst version of Express SCH.
What symbol should I use for the IRL520?· · Thanks

Rus

KenM

No picture with my previouse post. Let me try again.

Ken

Billboy

Ken,
You should check with ExpressPCB website about the placement of custom components in the library that you claim. A custom component should ONLY be placed in "SchComponents_Custom" once created. If you have any other questions, I may be able to help. I use and have used ExpressPCB product extensively for about 3 years. I have a very large custom schematic components library and a smaller PCB library. Custom PCB components should be placed in "PCBComponents_Custom".
Bill, KC9CFO

KenM said...
You could use a generic N channel FET, or get fancy and create a custom component, which I have done and uploaded to this forum.

There is also a picture of the component shown below. I believe you will need to save it to your express pcb "SchComponents_Library" folder. At least that is where it lives on my system after creating and saving the custom component.

Ken

KenM

My posting mistake.

The custom component is indeed inside the folder "SchComponents_Custom"

Yeah, I too have been using express PCB for about 4 years. Good service in my opinion.

Ken

Billboy said...
Ken,
You should check with ExpressPCB website about the placement of custom components in the library that you claim. A custom component should ONLY be placed in "SchComponents_Custom" once created. If you have any other questions, I may be able to help. I use and have used ExpressPCB product extensively for about 3 years. I have a very large custom schematic components library and a smaller PCB library. Custom PCB components should be placed in "PCBComponents_Custom".
Bill, KC9CFO

KenM said...
You could use a generic N channel FET, or get fancy and create a custom component, which I have done and uploaded to this forum.

There is also a picture of the component shown below. I believe you will need to save it to your express pcb "SchComponents_Library" folder. At least that is where it lives on my system after creating and saving the custom component.

Ken

Photon Artist

Thanks, Ken for posting the bitmap of the IRL520.

Using your image as a guidleline I went ahead and created a custom symbol for ExpressSCH.

I have created a schematic for using the stamp to drive the IRL520.· Is attached.· I would appreciate your you guys takig a look at it to make sure I got it lain out correctly.

Thanks again for the help!

Rus

KenM

Photon Artist said...

Thanks, Ken for posting the bitmap of the IRL520.

Using your image as a guidleline I went ahead and created a custom symbol for ExpressSCH.

I have created a schematic for using the stamp to drive the IRL520.· Is attached.· I would appreciate your you guys takig a look at it to make sure I got it lain out correctly.

Thanks again for the help!

Rus

Rus,
I viewed the schematic and the layout is correct. As you probably already know, when the stamp output pin is high, the relay will turn on.
One additional IMPORTANT note, you should connect a diode across the relay coil. Cathode (the end with the line) goes to the +12 side of the relay coil. Also, what resistor value to you intend to use? 10K to 1 meg will work.
Ken

Photon Artist

Thanks for checking out the schematic.· I can use all the help I can get!

I thought about the suprssion diode just after I sent the schematic.· I added an 1N4004.

I'll probably keep the value of the resistor low to keep switching speed up, not that it's that critical.

What value would you recommend?· Since this resistor connects the stamp pin to ground, I am assuming that it will keep it from floating?· Is that correct?

Thanks for the help



Rus

KenM

Photon Artist said...

Thanks for checking out the schematic.· I can use all the help I can get!

I thought about the suprssion diode just after I sent the schematic.· I added an 1N4004.

I'll probably keep the value of the resistor low to keep switching speed up, not that it's that critical.

What value would you recommend?· Since this resistor connects the stamp pin to ground, I am assuming that it will keep it from floating?· Is that correct?

Thanks for the help



Rus

Rus,
The resistor value recommended can be anywhere from 10k to 1 meg. You are correct that the resistor is to keep the gate from floating, as the MOSFET will not turn off if it is allowed to float once activated. Although if the gate is always connected to the stamp it

Photon Artist

Ken,

Do you remember what the recommended Pullup/Pulldown resistor value is for stamp pins?

I thought that perhaps I could kill two birds with one stone and use the recommended value to keep the stamp pin from floating, and perhaps at the same time keep the gate of the IRL520 from floating also.

Thanks for all your input.
Rus

KenM

As I understand it, a pull-up or pull-down resistor is needed only for an input pin, to force the input into a high or low state by default.

The Stamp pin that will drive the IRL520 will be an output, and therefore it will be in only one of two states, 5v or 0v, so a pull-up or pull-down is not needed.

To that end, some would also say that the Gate Source resistor in the MOSFET is not needed and I would agree. However, if the stamp loses power, I am not sure of the impeadance of the stamp pin, so the Gate Source resistor is a good practice to use it.

Photon Artist said...
Ken,

Do you remember what the recommended Pullup/Pulldown resistor value is for stamp pins?

I thought that perhaps I could kill two birds with one stone and use the recommended value to keep the stamp pin from floating, and perhaps at the same time keep the gate of the IRL520 from floating also.

Thanks for all your input.
Rus

Jon Williams

A gate pull-down won't hurt anything, and will keep the gate in a known state while the BASIC Stamp is initializing and its outputs are allowed to float.

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Jon Williams
Applications Engineer, Parallax
Dallas Office

RrIiCcKk

Hello all. I am looking for more library components for Express SCH or Express PCB. I do not find any in web search but did find this forum. Anyone here know of a site that may have a component library for downloading? Yes, I have made a few custom components, but was hoping to find download-able libraries. Or, if anyone here has any libraries they would not mind sharing, I would be interested.

Thanks in advance for your help...