Tested a MCP4261 by MEGA2560, the MCP became hot after half hour, what's wrong?
How can we follow that diagram? You have two completely different pin outs in each of the diagrams. Please try to draw comprehensible circuits, rather than make us
redraw them individually to figure out what's what!
MarkT:
How can we follow that diagram? You have two completely different pin outs in each of the diagrams. Please try to draw comprehensible circuits, rather than make us
redraw them individually to figure out what's what!
Thank you MarkT,
I redraw and attached the picture. I don't know how to delete the old one.
laoadam:
Tested a MCP4261 by MEGA2560, the MCP became hot after half hour, what's wrong?
It will likely be helpful to describe the situation with more detail. Sure --- it got hot after half an hour. But it will be helpful for everybody to know the conditions of operation.
For example ----- was the system doing exactly the same thing as when you first started it up?
Or the system was performing some particular operations during that half an hour.
How to reset the MCP4261?
If it kind of sort of works and it gets hot, you’re drawing too much current through the wiper(s).
Without seeing what both pots are doing, your guess is better than any one else’s since only you can see what they are connected to.
WattsThat:
If it kind of sort of works and it gets hot, you’re drawing too much current through the wiper(s).Without seeing what both pots are doing, your guess is better than any one else’s since only you can see what they are connected to.
Do you know how to reset the MCP4261?
Hmmm, the 'ol carbide cranium. How much current are you drawing through the part ?
JCA79B:
Hmmm, the 'ol carbide cranium. How much current are you drawing through the part ?
Didn't measure, the load is 4.7K + LED.
laoadam:
Didn't measure, the load is 4.7K + LED.
It looks like it's hard for you to get a proper answer here until you show the full details. Your images that you posted showed none of what you mentioned above. So nobody can properly help you unless you first help yourself to describe the situation (the actual circuitry you used) with adequate detail - such as what you had done, and what code was used, and whether the system was actually doing what you wanted it to do for say 25 minutes (remained cool) ..... and then all of a sudden got hot. At the moment, you haven't provided enough information that allows anybody to trace your issue in an efficient way.
laoadam:
Didn't measure, the load is 4.7K + LED.
The maximum current through the wiper is 2.5mA, so the LED is likely drawing too much.
BJHenry:
The maximum current through the wiper is 2.5mA, so the LED is likely drawing too much.
BJ ..... is that a 5V system? Not sure what their connection is ... but 4.7 kohm across a bare 5V system would give around 1 milliamp? Still don't know what their set up is. Was just asking only.
Southpark:
BJ ..... is that a 5V system? Not sure what their connection is ... but 4.7 kohm across a bare 5V system would give around 1 milliamp? Still don't know what their set up is. Was just asking only.
That's a good point. Max VDD is +7V. I had assumed that the LED wouldn't be working with so little current and so the OP must have gotten the resistor value wrong.
Hi,
Can you please post a copy of your complete circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
What are you connecting the digital pot too?
Does it have more than 5V on it from the circuit you are trying to control?
Thanks.. Tom... 
BJHenry:
That's a good point. Max VDD is +7V. I had assumed that the LED wouldn't be working with so little current and so the OP must have gotten the resistor value wrong.
Totally agree with you BJ.
Thanks to all.
Here update the result, the MCP was hot cause of the large current.
One more question, how can let the MCP keep the value wrote for a little while say 3-4 seconds?
You set the value and it will keep that value until you set another value. You just choose how often you want to send a new value to it.
laoadam:
Thanks to all.
Here update the result, the MCP was hot cause of the large current.One more question, how can let the MCP keep the value wrote for a little while say 3-4 seconds?
What large current, what are you doing with the output of the MCP?
Tom....
Thank you for asking, the resistance attached to the LED is 200 Ω, resulted a large current draw.
laoadam:
Thank you for asking, the resistance attached to the LED is 200 Ω, resulted a large current draw.
Are you adjusting the brightness of a LED with the digital pot?
Why aren't you just powering the LED with series resistor and PWM output of the Mega?
Tom..