11
votes
Accepted
What happens if an MCU boosts its own supply voltage while running?
I've done that with an ATtiny84 with no problems.
When in sleep mode parts of the circuit (such as the analog section) are powered down and the supply voltage is dropped from 5V to 1.8V with only the ...
- 32.6k
4
votes
Accepted
Exploding/superhot capacitor in XT AC-DC PSU
The power supply schematic indicates this is a flyback converter, total output power rating = 80W (sum of output power rating of all rails), which is quite modest by today's standards. Your load, ...
- 1,542
3
votes
How do I run four 1 watt 3.4 volt LEDs with a 5 volt 2 ampere power supply without overheating?
Do some math and use ohm's law.
1 watt at 3.4 volts implies a current of 294 mA through each LED. If you use a dropper resistor, that resistor would need to drop 1.6 volts whilst carrying 294 mA. That ...
- 443k
2
votes
Clock Driver - What's wrong with my H-bridge design?
Q1 dies because its gate-source voltage goes outside its limits. As you can see from the datasheet, its maximum allowed gate-source voltage is ±12V.
But once you enable it, the gate-source sees -24V (...
- 30.2k
2
votes
Exploding/superhot capacitor in XT AC-DC PSU
The circuits are unrelated in a sense, but also coupled through the flyback transformer.
Both of these caps were 1000uF 16V, maybe there is a design error or manufacturing error, and cap model not ...
- 137k
2
votes
USB C - USB A cable connection for power source
In order to get 5v out of USB-C — with no data negotiation — you have to pull the cc1 and cc2 leads low, through 5.1k resistors iirc. I just did a PCB like this, and it worked.
- 29
1
vote
Electromagnet design and powering it up? (Fault prevention of DC supply for a small coiled Electromagnet)
This has started somewhere from the middle. You have already nailed how much space you can have per a coil. Ok, but then you should test what number of ampere turns creates the needed force effect to ...
- 1
1
vote
Accepted
Electromagnet design and powering it up? (Fault prevention of DC supply for a small coiled Electromagnet)
With your poor magnetic circuit - the iron core only halves the length of air that your H-field has to push flux through - you are going to need all the Ampere.Turns you can get, as it only doubles ...
- 162k
1
vote
AC and DC inputs to a Power Supply
I suggest buying an off-the-shelf PSU to generate an isolated 420VDC from the AC supply (assuming the 12V PSU can handle 420V at its input). I suggest this because the power level is up to 1kW, which ...
- 1,542
1
vote
Best way to go from 5V to .95V to power an FPGA at max 15A
Looking at the Renesas Rad Hard Switching Regulators which has been filtered to select regulators which can supply a maximum of 15 A there are the following which might meet the requirements:
...
- 1,467
1
vote
Best way to go from 5V to .95V to power an FPGA at max 15A
A brief search on TI's website reveals a handful of space-rated buck controllers, several of which are capable of output voltages as low as 0.604 volts. In particular, the TPS7H4003-SEP and TPS7H4001-...
- 30k
1
vote
Best way to go from 5V to .95V to power an FPGA at max 15A
You didn't say what your 5 V current requirement is, apart from your notional concept of generating the 0.95 V 15 A supply from the 5 V supply.
But I think you should generate both your 5 V and 0.95 V ...
- 10.3k
1
vote
Best way to go from 5V to .95V to power an FPGA at max 15A
I think you could coerce the PE99155 into making 0.95V by inserting a voltage divider between EAINP and VREF. Check with the Teledyne apps folks. (You did, they vetoed it.)
It's also possible to ...
- 51.1k
1
vote
What do I need to power a Christmas village with mains instead of batteries and in a single circuit?
If you use that circuit what will happen when you turn any of the potentiometers all the way down is the power supply will be shorted out and the pot will likely burn up. The wipers are connected to ...
- 19.5k
1
vote
Accepted
Speaker and buzzer sound levels issues
You are using a button cell battery as 3V supply for driving an 8 ohm speaker, and the CR2450 battery is not up to the task in any way.
A speaker is basically 8 ohm resistance. The speaker amplifier ...
- 137k
1
vote
Need cheap variable positive/negative switching bench power supply with CC
To provide a formal answer, here is my take.
For hobby use where noise and minor inconsistencies don't matter, your design will do exactly what you need it to do.
I would suggest connecting a dual-...
- 326
1
vote
Accepted
Using two supply rails (on supply and output pins) with 74HC595
That's not a good way of doing it.
This is even said in the data sheet; outputs should not be pulled above VCC, and 70mA total current should not be exceeded, and you are doing both.
If 5V supply ...
- 137k
1
vote
Using two supply rails (on supply and output pins) with 74HC595
Just a first note: You are not connecting 5V supply to the SR output pins, there are the resistors and LEDs in series. These limit the clamp current to \$I_{OK} = {(V_{Supply} - V_{f} - V_{OH}) \over ...
- 2,501
1
vote
Schottky diode fails probably due to temperature - LED driver
If the LED Vf is lower, the MOSFET duty cycle will be lower also, and the diode will conduct for longer during each cycle.
If current stays the same, diode dissipation is directly proportional to the ...
- 71.9k
1
vote
Can I give DC 12V to a AC 12V input?
Linear regulators like 7812 needs 2v or more above the output voltage as input in order for them to work properly. Example, you want a regulated 12v dc output, you have to at least give an input of ...
- 11
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