I'm looking for an I2C controllable PWM generator IC, preferably under a buck a piece and with at least 4 channels. Should not require flashing of a firmware first unless that flashing can be done through the same I2C connection..
Any ideas?
I'm looking at this https://www.alldatasheet.com/datasheet-pdf/download/1148542/AWINIC/AW9523B.html gpio expander, which has a current source LED drive mode. Rather than directly controlling a pwm duty cycle one can set an output pin to be driven at a specific fraction of 37mA output current. What I wonder is, could this still be used to control a H-bridge that drives a DC motor and use this LED mode to control the motor speed? In particular I'm thinking of this H-bridge: https://www.mouser.com/datasheet/2/408/TB67H451FNG_datasheet_en_20191111-1713881.pdf
I'm not sure what I'm doing wrong.
I create a schematic for the first group of components
I draw a rule area around that group
I "Place Directive Label" at the rule area and name the component class "H-Bridge 1"
I create 5 copies of that group and update the names of the directive label of each group's rule area
I update the PCB from schematic and layout the first group of components
I go to tools -> multi-channel -> "generate placement rule areas" and select all 6 component classes and click ok
I shift around the components so that each group is exactly within its generated rule area - no overlaps
I go to tools-> multi-channel->"Repeat layout" and select the rule area of the first component group that I have already layouted
Now in the "repeat multichannel layout" window that pops up I could select H-Bridge 2 a H-Bridge 6, but each of them has the status "component count mismatch", even though each area contains exactly the same amount of components (4).
If I nevertheless select them all and click ok I just get the message "copied to 0 rule areas" and nothing happens.
What am I doing wrong?
I'm not sure I understand the constant current mode and PWM interaction of this motor driver https://www.avnet.com/wcm/connect/c45441f8-7188-4bb3-9133-2bdda859d2ea/TB67H450FNG_application_note_en_20190510.pdf
Page 5 reads
> 4. Direct PWM Control 4.1. Input and Output Functions A speed of the motor can be controlled by Inputting PWM signal to pins IN1 and IN2, and operating them with PWM control. When the constant current function is disabled, RS pin should be connected to GND, and the voltage of 1 to 5V should be applied to VREF pin.
And Page 6 reads
> 5. Constant Current PWM Control 5.1. Constant Current Control Type (Mixed Decay) In this product, a constant current threshold (NFth) is set by the current detection resistor between RS and GND, and VREF input voltage. When the output current reaches the threshold due to forward rotation and reverse rotation, the constant current control is performed in Mixed Decay mode. In case of the constant current control, the OFF time (toff) is fixed to 25 μs (typ.) to determine the pulse width of the current (current pulsating flow). The percentage of Mixed Decay Mode is as follows; Fast Mode: 50% to Slow Mode: 50%
Does that mean if I want to use PWM I have to disable the current cap by connecting RS to gnd? Can't I set a max current AND apply a pwm signal to IN1 and IN2?
What's the point of diminishing returns? What's the point at which the lost surface area hurts thermal flow more than the added vias?
I sometimes see on PCBs with high current application thick copper bars soldered onto the power rails.
I wonder, when getting PCBA, could a 'poor man's" version of this be to copy a trace into the solder mask and paste layer so that it will be covered by solder and thus have a larger cross-section to carry more current?
If this is practicable, what would need to be considered? Is there a minimum trace width below which it won't work? Is there some rule of thumb by what factor the trace width can be reduced while having equivalent current capacity when covered by solder like this?
Also: could I make the paste layer width slightly larger than the solder mask opening, so that the surface tension will pull the solder from the sides onto the trace when it melts, making a thicker solder covering? If so, how much wider could I make the paste layer trace than the solder mask opening?
I recently stumbled over the ICs of awinic and at least on paper they are pretty damn good and have small footprints. JLCPCB has some of their ICs on stock but for other products where their stock is 0 I was unable to source the components through JLCPCB. I wrote to awinic but they told me that they are unable to conduct business directly with individuals.
Does someone have an idea where I could get them? In particular I'm looking for AWD8912TSR https://doc.awinic.com/doc/202312/832ca276-8e2d-4b06-8265-5702e7607ffc.pdf
I tried multiple times to use the "request quote" function but the request always gets closed quite immediately with the status "quote failed" and no further message about the reasons. So I guess I'm doing something wrong.
What needs to be entered as target unit price? The unit price stated by the vendor? The maximum amount I'm willing to pay per unit? The price I hope to get per unit)?
And what abou "target lead time"? Is that the maximum time I'm willing to wait? The time by which I'm ready to place a PCBA order?
Is there a minimum total amount that needs to be reached?
The thing is that the part itself has already an entry in the parts database but with an incorrect estimated unit price of $0.0201 and a minimum pre-order of 443 units. I see that wrong price estimate of $0.0201 with 443 minimum order on quite many items that have 0 stock so I assume that the minimum total amount of a pre-order needs to be at least $8.90 but if I preorder the minimum amount of 443 (which I guess is calculated based on the wrong price estimate), then with the correct price it will cost around 100$ (I need only 10 now).
When I talked to the support about this issue they told me I should use the "request quote" function instead of the "pre-order" function, but my quote requests always fail and I don't understand why...
This is a 2 layer motor shield for 6x brushed bidirectional DC motors, configurable from 4.5-25V (5A total) and 2x 5V servos (2A total), powered by 1S lipo or lifepo4 battery (charging circuit is off board).
Would appreciate a sanity check 🙏🏻
4.5-25V boost converter: https://www.ti.com/lit/ds/symlink/tps55340.pdf
5V boost converter: https://xonstorage.z8.web.core.windows.net/pdf/everanalog_ea2208t6r_apr22_xonlink.pdf
12x half-bridge: https://doc.awinic.com/doc/202312/832ca276-8e2d-4b06-8265-5702e7607ffc.pdf
Better resolution pictures in case reddit compresses too much:
kicad_screenshot: https://i.ibb.co/RkkSBBPV/blended.png render: https://i.ibb.co/XxRzm9sQ/motor-shield.jpg front copper: https://i.ibb.co/kV07mTQr/Motor-shield-f.png back copper: https://i.ibb.co/fVJDW3hL/Motor-shield-b.png schematic: https://ibb.co/xKXWb06C
Thank you!
This is a 2 layer motor shield for 6x brushed bidirectional DC motors, configurable from 4.5-25V (5A total) and 2x 5V servos (2A total), powered by 1S lipo or lifepo4 battery (charging circuit is off board).
Would appreciate a sanity check 🙏🏻
4.5-25V boost converter: https://www.ti.com/lit/ds/symlink/tps55340.pdf
5V boost converter: https://xonstorage.z8.web.core.windows.net/pdf/everanalog_ea2208t6r_apr22_xonlink.pdf
12x half-bridge: https://doc.awinic.com/doc/202312/832ca276-8e2d-4b06-8265-5702e7607ffc.pdf
Better resolution pictures in case reddit compresses too much:
kicad_screenshot: https://i.ibb.co/RkkSBBPV/blended.png render: https://i.ibb.co/XxRzm9sQ/motor-shield.jpg front copper: https://i.ibb.co/kV07mTQr/Motor-shield-f.png back copper: https://i.ibb.co/fVJDW3hL/Motor-shield-b.png schematic: https://ibb.co/xKXWb06C
Thank you!
I love pigeons! On the webpage of city zurich https://www.stadt-zuerich.ch/de/umwelt-und-energie/natur/tiere-in-der-stadt/tauben.html#massnahmen_zur_reduzierungdertaubenpopulation they write that the city is operating three dovecotes. Does someone know where they are and whether it is possible to visit them? The webpage unfortunately doesn't mention anything further about them.
With PCBA from jlcpcb or pcbway.. there are no components on the backside. If soldering myself I don't see a problem, and afaik through hole components are soldered by hand anyway, but do you think that could pose a problem nevertheless?
I have a motor driver that specifies a 100nF cap and a 470uF cap on the input. If I have 4 such motor drivers fed by the same power supply, can I replace the 4 470uF capacitors with one 2000uF capacitor?
For those who say "eye-squared-see" - do you pronounce I3C as "eye-cubed-see" or "eye-three-see"?
Do you need to interrupt the charging so you can measure cell voltage or is there a way to do it concurrently?
Is it just a lack of software or is hardware missing? If so, what hardware exactly?
I want to make a toy model where the whole thing is made from a pcb with mouse-bites to break off the individual parts, and then you assemble it by soldering the parts together.
Jlcpcb and pcbway both charge extra for each individual piece that is separated by mouse bites, even though the whole thing is ultimately one thing.
Are there low cost chinese pcb manufacturers that will allow break off parts with mouse bites without charging extra for each part?
I'm looking for a cheap SMD component (preferably one available in jlcpcb's parts library) that is both paramagnetic (meaning it will stick to a magnet while not being magnetic on its own, like for example a piece of iron) as well as having a conductive housing (so that when it will stick to a magnet it also creates a conductive path to it)
I know that there are connectors with pogo pins and magnets (though here the magnets themselves are just part of the housing, not conducting thrmselves), but I need something smaller. Just some smd component that's paramagnetic and has a conductive housing. Any ideas?
I have a PCB with 78 different components in the BOM, all picked from JLCPCB's parts library - except one part is out of stock and for some reason jlcpcb is incapable of ordering it. I can order it myself and could then consign it to jlcpcb, but apparently when I consign the part to them myself, then I need to also consign all 78 other parts (or find them through global sourcing) as well?
Does someone know the rationale behind this and whether there's some way around that?
I see some drones with red lights in the front and green lights in the back, and some Other ones with red lights to the left and green lights to the right. Is one arrangement preferred over the other and if so why?
