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L1 and Q4 form a bosst converter to be able to use LEDs that need a higher voltage than we can provide. So we want to switch Q4 and we want to switch it fast (to keep switching losses low). MosFET are controled by voltage on the gate. But they also hae a cpacitance between that cate and the channel. To change the voltage on a capacity we need current. That's ...


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Q4 and L1 form a boost converter circuit along with the LEDs. R5 etc is just the gate drive for Q4.


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Have you considered instead the WROVER module, which already has integrated SPI RAM? Where did you get the idea QSPI isn't supported? The WROVER uses QSPI for its integrated SPI RAM, and both modules use QSPI for the integrated flash. Even if you really must stick with the WROOM and add your own SPI RAM, the WROVER is proof that it's possible to add your ...


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From the LY68L6400 datasheet based on Table 2 : As you use the SPI mode I would leave SIO[2] and SIO[3] pins floating. Worst case it should not you can solder a little wire to ground or VCC. If you plan on making a 3rd "production" PCB you can put jumpers on the SIO[2] and SIO[3] pins and try different possibilities


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Briefly, there are two reasons: there's more to resistors than current limiting, current limiting is still needed around integrated circuits. In the digital world, you'll often encounter pull-up and pull-down resistors. These serve to set a "default" voltage for a pin or bus, when the chip is not actively driving it. This is the case for the ...


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The resistors are the R part of the Ohm's law. You should really start with it, because your assumption that "they restrain the flow of current to protect the components" isn't a complete "picture". Now when you are asking to describe ADS1115 board, instead of submitting a picture of it, you can searched for a schematic instead. Because ...


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I don't see much wrong with it, a little confusing why you would need the fuses. Another way (more complex way) to implement current protection would be to detect the current with an analog circuit and cut enable line if the current get's too high. With the battery you also may want to consider a regular DC/DC converter because the design is probably already ...


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It means that it is a bus with multiple signals. It can't be used to determine anything specific about the I2S bus, such as data direction or clock direction, but generally I2S devices are quite versatile that they can receive clocks from another device or send clocks to another device.


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The leds use a typical NZR single wire protocol, reading the data like a shift register. They accept 24 bits to determine their state, and then pass along the rest of the data out of DOUT to the next led which does the same, until they receive a reset signal. This is how most smart individually addressable leds work, as a serial chain. Individually ...


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These are multiple electrolytic capacitors in a single package. The package would have more than the usual 2 pins, one for each capacitor and a shared ground pin. Each non-ground pin would have such a symbol next to it to identify it. The markings on the side would then state the symbols and their respective capacitances/voltages. Here's a picture of such a ...


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No, generally voltage regulators can't be paralleled, and in this case even the datasheet forbids it. Some regulators can be paralleled, and they can have a special connection between them to communicate how to share the load. The problem is the regulators are not identical, they have output tolerance. If one regulator outputs 4.99V and the other one 5.01V, ...


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It means the current is sensed. Likely via current sensing resistors in those lines, or sensing FETs (and combined for push- and pull stages). In an IC it's not likely to be a magnetic (Rogowski coil) sense technology. Note the datasheet says: "The outputs are fully protected against shorts to GND, VCC, and output-to-output shorts..."


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I would like to add that the missing grounded C connections are much smaller than TI's datasheet, but exist with the close proximity of the aluminum backplate attached to PCB ground for EMI suppression and therefore has an equivalent circuit, if you also used a similar grounded backplate. If the circuit is balanced by good component and parasitic ESL ...


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Thanks for a well presented question. Page 19 of the referenced TI datasheet suggests the output filtering is optional. Depending on the target market and the exact application, Sony have determined it was not necessary. They may have put a common mode choke on the speaker wires. TVs are a high volume product and heavily cost engineered to specific markets. ...


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EDIT : "other" example of power supply. Not completely tested. Current limiting topology. Low voltage op-amp used. Post useful Using a power schematic like this one, a general op-amp may be used. For reference, TRANsient analysis ... An AC Analysis ...


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When ordering a professional PCB, you can pay for a Flying probe test (wiki) which basically checks how each contact on PCB is connected to other contact (in order to check if PCB was manufactured without errors). This same machine is perfect for automating your problem in an easy way. First remove all components with heat gun (removing components is very ...


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A method I've used in the past is to take a picture of the PCB and then import the picture into a schematic capture program. You can even draw components and wires over the picture of the PCB. Once you are done you'll have a bad looking schematic (because all the wires will be mixed up with this location on the PCB). Copy the schematic or remove the picture, ...


5

Take good photographs (If single sided, use a light box) then scale, flip and combine the two photos of the sides of the board so you have a picture showing the copper AND the components. It is not a horrible idea to doctor the photo of the copper so that the copper shows up in some garish colour before merging the pictures. If more then two layers you are ...


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The resistor is marked green most likely because it is a component that is marked not to be mounted during manufacturing, just like U3, as these are marked "(NC)". The use of green box can't be guessed from the context in any way. It might be an internal marker for something, like this has changed from previous version, or this needs double ...


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According to OrCAD/Allegro terminology, they are busses and/or netgroups. They are both signals grouped together visually into a single line on the drawing for readability. Netgroups are just busses where member signals are given individual names instead of numerical identifiers. But at the top level it displays (n:m) just like a bus to display how many ...


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It means that the signal is a bus. There are multiple individual wires/connections and they are numbered using the range of integers shown on either side of the colon. So, I2C(1:0) is really two separate signals: I2C1 and I2C0. Some CAD tools would consider them to be I2C(1) and I2C(0) but the idea is the same. In many cases the particular number associated ...


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Developers might changed schematic without changing PCB. Usual practice.


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They allow users to remove resistors to disconnect the ESP from CP2102 and connect them for other purposes.


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What do the specs say for the voltage on CTRL? Why the fuses? The fuse is to protect the wire, not the load so what value are the fuses adding? As for input and output filters, it depends. What are the standards you need to comply with? You probably don't need to worry too much about input filtering as the battery won't care and the wiring is probably short. ...


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