Timeline for Switching regulator circuit failing
Current License: CC BY-SA 4.0
20 events
| when toggle format | what | by | license | comment | |
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| Jan 30, 2023 at 3:41 | vote | accept | Feynman137 | ||
| Jan 22, 2023 at 11:13 | history | edited | JRE | CC BY-SA 4.0 |
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| Jan 22, 2023 at 8:11 | answer | added | Lars Hankeln | timeline score: 3 | |
| Jan 22, 2023 at 7:54 | comment | added | greybeard |
(I forget: With nothing connected to MotorON, beware LED D102 doubling as a photocell: Measure its current "driving" two series connected diodes when exposed to light.)
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| Jan 22, 2023 at 7:36 | comment | added | greybeard | Is any load connected during these tests? Seeing \$V_{IL,EN}max\$ .6 V, I'd add a pull-down there(~.33M). (And pulse EN with 2*soft start time and low duty cycle, given the equipment.) | |
| Jan 22, 2023 at 7:30 | comment | added | greybeard |
flat 0V on output and a flat 14V on the input. Inductor saturation current for SRP3212-2R2M is 4.8A, [input] Current limit is 4A Please edit everything inviting useful answers into the body of your question.
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| Jan 22, 2023 at 7:17 | comment | added | PStechPaul | I've had similar problems where a newly assembled PC board developed leakage paths and short circuits. I found that a thorough scrubbing with flux remover (alcohol), followed by detergent and clean water to remove ionic contaminants, and finally hot air, pretty much fixed the issue. | |
| Jan 22, 2023 at 4:11 | comment | added | Feynman137 | Everything is wired up, the power supply is running but not yet controlling to 14V, then I enable it and it goes to 14V. Current limit is 4A | |
| Jan 22, 2023 at 4:07 | comment | added | Tim Williams | How are you powering it? Wiring it up then enabling the power supply? Or enabling the power supply (set to 14V DC out and some current limit I guess) then plugging it in? | |
| Jan 22, 2023 at 4:00 | history | edited | Feynman137 | CC BY-SA 4.0 |
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| Jan 21, 2023 at 20:35 | comment | added | Feynman137 | O-scope shows a flat 0V on output and a flat 14V on the input. Inductor saturation current for SRP3212-2R2M is 4.8A. I think this is sufficient. I don't understand why those pads are showing such low resistance to ground. | |
| Jan 21, 2023 at 17:57 | comment | added | Andy aka | Circuit wise it looks good (cursory look) | |
| Jan 21, 2023 at 17:56 | comment | added | winny | How does the oscillogram look like before it fails? What’s your inductor peak current rating? | |
| Jan 21, 2023 at 17:48 | comment | added | Feynman137 | Minimal wire length I'd say 2ft. This is the first time I am trying this circuit, no it has never worked. The motorON signal comes from a multivibrator IC but I have verified that it is outputting 3.1V which is above the EN high threshold voltage. | |
| Jan 21, 2023 at 17:37 | comment | added | Andy aka | What wire length between power source and your circuit? Has it ever worked (this bit's important to know). Where does the MOTOR_ON signal come from and, what is it connected to? | |
| Jan 21, 2023 at 17:35 | history | edited | Feynman137 | CC BY-SA 4.0 |
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| Jan 21, 2023 at 17:29 | history | edited | Feynman137 | CC BY-SA 4.0 |
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| Jan 21, 2023 at 17:29 | comment | added | Feynman137 | Good point, let me update but right now I am testing with a variable voltage regulator so it should be a clean 14V. | |
| Jan 21, 2023 at 17:27 | comment | added | Andy aka | If it's an automotive design then the MAX20077 will fail quite often due to automotive surges etc.. It's only got a max rating of 36 volts and this is weedy compared to what line surge voltages you can get in automotive. Ignore if not automotive but, you should definitely state where the input source of power comes from. | |
| Jan 21, 2023 at 17:18 | history | asked | Feynman137 | CC BY-SA 4.0 |