Activity for DeadMouse
Type | On... | Excerpt | Status | Date |
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Comment | Post #291038 |
You are right about R18. I think it should be lower at around 1K.
Regarding the 3.2mA it is fine. I have tested that already and it worked without issues. I could also make it a bigger value.
Another issue is how to merge the TX and RX lines so I can have only one but also maintain the protecti... (more) |
— | about 2 months ago |
Comment | Post #288784 |
Would you mind to elaborate the reasons why you would not add a ground pour on top/bottom layers? (more) |
— | 10 months ago |
Comment | Post #288784 |
I posted some pictures that show how bypass capacitors are placed around the chip. Notice that some of them cannot have direct connection to their relative ground pins of the chip cause sometimes the ground pins are not physically close to the power pins and other gpio pins there are in between them.... (more) |
— | 10 months ago |
Comment | Post #288784 |
Regarding bypass capacitors you mean to avoid connecting them directly to the internal ground plane using a via?
Do you mean that they should be connected to the ground pins directly using traces or local planes and connect all of it together to the internal ground plane? (more) |
— | 10 months ago |
Comment | Post #288784 |
I'm not sure I understand your point about the ground plane being a center-fed patch antenna.
I didn't mean there's only one via that connects every ground from the top layer to the internal ground plane.
I have placed vias close to every pad that is connected to ground and using a trace or a ... (more) |
— | 10 months ago |
Comment | Post #288515 |
Why do you prefer a voltage divider over a zener diode? (more) |
— | 11 months ago |
Comment | Post #288515 |
NPN version.
Thanks, Olin.
I concluded you like more the NPN version versus the MOSFET version.
Regarding your last schematic.
R1-R2 form a voltage divider and the threshold is around 11V at the input. At this voltage, the Vbe will be around 0.7V and it is enough for the BJT to star... (more) |
— | 11 months ago |
Comment | Post #288474 |
Thanks! That's helpful (more) |
— | 11 months ago |
Comment | Post #288440 |
Also, a simple inversion won't do the trick. I added a truth table that shows the output with 3 differnt types of input for each option.
For example, if you just put a NOT gate on Option 1, you will not get Option 2. (more) |
— | 11 months ago |
Comment | Post #288440 |
Adding the inversion in the firmware would require one more pin from the chip.
I need total 36 inputs that would be able to invert independently. That is 72 pins total. One for the input and one for its selection control. That's why I want to handle this in the hardware side (more) |
— | 11 months ago |
Comment | Post #287265 |
I'm not sure I can achieve such steep skirts with discrete components.
I'd aim for 100KHz bandwidth but 300kHz is much easier to achieve with discrete parts.
Would there be any problem if the skirts were not that steep?
And yes, I noticed that ceramic resonators are very hard to find at a f... (more) |
— | over 1 year ago |
Comment | Post #287263 |
Thank you very much for your answer.
I am pretty sure that my problem is the tight bandwidth of the Murata part as you mention.
I'll try out a bandpass filter using discrete components and maybe find another suitable part. I'll also try a direct communication off of power line by connecting t... (more) |
— | over 1 year ago |
Comment | Post #287262 |
You probably mean connecting the outputs (right part of C4) together and off of DC line, right?
Thank you! I'll try it.
Regarding the main question, what's the difference between those two components above (a ceramic filter and a ceramic resonator)?
Is the part I found suitable for that ... (more) |
— | over 1 year ago |
Comment | Post #287262 |
Datasheets and screenshot added.
What do you mean by exclusive connection?
The tests are on a bench and the devices are communicating over a DC line of 24V. (more) |
— | over 1 year ago |
Comment | Post #286104 |
"Note C3 to provide stability, and R2 to provide some impedance for C3 to work against. "
What does R2 really do here?
Could we use the same topology C3 along with R2 on the other circuit above? (more) |
— | about 2 years ago |
Comment | Post #286110 |
What I'm calculating is
$$D=\frac{20\text{V}}{-24\text{V}-20\text{V}} = -0.45... $$ (more) |
— | about 2 years ago |
Comment | Post #286104 |
I did not understand the negative regulator part you're talking about. How would that work? (more) |
— | about 2 years ago |
Comment | Post #286103 |
I don't mind about wasted power. The device will be inside the lab always. (more) |
— | about 2 years ago |
Comment | Post #286103 |
You are right. At first I would be happy to have around 0.1% error. I was thinking of using a 12 bit DAC. (more) |
— | about 2 years ago |
Comment | Post #286103 |
The upper voltage across the load can be a little lower if we calculate the voltage drop across the current sense and the power element. I wouldn't mind even if that voltage drop was around 6V or even 8V. On the other hand the low voltage across the load must be closest to zero possible. (more) |
— | about 2 years ago |