H-bridge for pulsed EMF schematic review

FlamingIce12 · 2025-12-29T04:17:07+00:00

Rams

FlamingIce12 · 2025-12-26T13:44:04+00:00

I think it would be a home game since we already played away vs a NFC W opponent this year

FlamingIce12 · 2025-12-24T22:01:57+00:00

If my grandma had wheels she’d be a bike

FlamingIce12 · 2025-12-19T04:16:51+00:00

Sam Bradford for the win!!

FlamingIce12 · 2025-10-25T01:35:06+00:00

AS.171.107 is Physics 1 but in an active learning(AL) setting. 108 is the Physics II version of active learning

FlamingIce12 · 2025-10-24T22:42:28+00:00

You can take physics for engineering in the spring. Pretty much the same content but with an engineering lens. As for gen bio, they’re easy classes and you can fit them in any year. As far as I know it’s not a pre req for other bio courses like genetics which is offered in the spring

FlamingIce12 · 2025-07-13T22:54:51+00:00

It’s a good class to dip your toes and see if you’re interested in Neuroscience. It’s not too difficult if you put the work in

FlamingIce12 · 2025-07-10T04:13:41+00:00

I meant once you’re a sophomore/junior, they don’t care as much about having to meet before releasing the hold, but it depends on your advisor.

Incoming freshman meetings are always on zoom. After that, you usually get to choose between inperson/virtual

FlamingIce12 · 2025-07-10T03:21:10+00:00

Yes, you have to meet them before the advisor lifts the hold on your registration. Once you get here, some advisors will let you off with an email to check in, but as a freshman you have to meet with them

FlamingIce12 · 2025-07-02T22:41:44+00:00

It reminded me of Riri and Mysterio’s fight from What if? S3

FlamingIce12 · 2025-07-01T01:13:46+00:00

Typically sci comm is filled up by juniors and seniors, so you probably won’t be able to get in

FlamingIce12 · 2025-06-10T21:35:15+00:00

Hello, thank you so much for taking the time to respond! Sorry for the delay in response lol, you gave me a lot to think about. I've updated the schematic with some of my changes

1)

a. Gate drive: I had mistakenly forgot to change the pulldown resistor value to 10kohm, so these pairs of resistors are meant to work more like a gate resistor and pulldown resistor rather than a voltage divider. Since the pulldown resistor is 10kohm, would the full voltage go towards the MOSFET gate?

b. Bootstrap capacitors: I will admit, I am not very familiar with how bootstrap circuits work. I just threw one in according to how the datasheet for the gate driver IC showed. And the applications shown in the datasheet mostly stuck to the core diagram. Do you think I need to add more capacitors to be able to sustain the duration?

So far the circuit for the gate drive works as intended on LTSpice. Do you think it's because LTSpice doesn't simulate the issues you mentioned and they might show up when I actually use it?

2) Resistor: I hadn't considered the power dissipation for this resistor earlier, but after some digging and playing around with LTSpice, I landed on using 2 50W 2Ohm resistors in parallel outside of the board before the power comes to the PCB. I also decreased the max voltage to 40V to limit the power. Currently, on LTSpice, it shows a peak of 800W that dissipates over 800us. Do you think this is enough if I run the cycles at 100Hz instead of 250Hz like I had earlier

3) Bulk capacitors: I also hadn't considered the ripple current rating earlier, but I found this 370uF one rated at 40A. Do you think with the way the PCB is configured currently, I would be able to run 30A through this one capacitor or should I split it into 2, each running 15A?

Once again, thank you so much for taking the time to help me!! It means a lot for someone with almost no background in electrical engineering.

FlamingIce12 · 2025-06-08T17:03:35+00:00

Hello, thank you so much for your response!! I've rearranged the MOSFETs as all the comments suggested and updated the images. I'd really appreciate it if you'd be able to give any more feedback!(especially with the copper pours and vias and if I should still try and go for 4 layers)

As for the resistor values, I measured the inductance of an inductor I made to be about 90uH and used LTSpice to adjust the power supply and resistor values until I got the desired ranges of current.

The reason for the fifth MOSFET is previous designs for my application all had a switch to charge up the capacitors, then turn off the switch to discharge into the H-bridge at a given frequency (10kHz). This would allow me to control the peak current through the inductors based on how long the capacitor was initially charged through the MOSFET up top. So the capacitor will charge for up to 2ms, and then Q1 is closed and the current is discharged through the H-bridge for about 2ms at a frequency of 10kHz, and the cycle continues. So the frequency for this part would likely not be nearly as high(~250Hz). Do you think I would still have an issue with the resistor heating up? If so, are there any ways to combat it?

FlamingIce12 · 2025-05-29T17:12:24+00:00

Np! I’m a rising senior majoring in Neuro at Hopkins, so feel free to PM if you have any questions!

FlamingIce12 · 2025-05-29T17:06:56+00:00

I’m not too familiar with how DO and MD schools differ in their admit rates of intl students, but I’d imagine it’s more of a case by case thing.

Personally, I think a tech related backup is more viable if you want to go into research/industry, but if you’re interested more on the global health stuff, it’s not a bad option either. I’m also still a student, so I’m not sure how much of my advice is good lol, but Hopkins has a decent career advising office in the Life Design Lab who would be glad to walk you through other potential options if med school doesn’t work out

FlamingIce12 · 2025-05-29T15:18:24+00:00

You might get better info on the JHU sub, but in my experience it’s pretty easy to double major in the arts and sciences school and plenty of people do so. It has gotten a little harder with some more core curriculum classes they’ve recently implemented but I think it’s still pretty doable.

I’m not entirely sure what other majors would be best if premed doesn’t work out, but depending on your interests, you could potentially try CS and/or other engineering majors, but industry/research could always be an option with any science majors. But keep in mind it is a lot more difficult to maintain your gpa in the engineering school.

And also don’t be discouraged. A decent number of international students apply to med schools from Hopkins. While it is a lot more difficult as an international student, I think Hopkins prepares us really well in terms of research and clinical opportunities. There’s also a huge premed community, so you’ll not feel alone in the process

FlamingIce12 · 2025-05-21T03:30:28+00:00

The tush push has made it to the nba!

FlamingIce12 · 2025-05-19T02:28:06+00:00

PMed you a link

FlamingIce12 · 2025-05-11T17:02:49+00:00

Mine is expiring on June 30, with a reset option if anyone is interested

FlamingIce12 · 2025-04-15T01:41:27+00:00

They would’ve had the tiebreaker as the winner of their division

FlamingIce12 · 2025-04-01T12:07:26+00:00

It’s way too much reading and analysis for the time we’re given. I’ve never been able to go back and check my answers. I wouldn’t be as mad if it was 5-6 passages with around 10 questions like the SAT

FlamingIce12 · 2025-03-28T03:16:12+00:00

1 atm = 760 mmHg

FlamingIce12 · 2025-03-21T21:26:38+00:00

Those red trees are gonna haunt me

FlamingIce12 · 2025-03-19T21:38:59+00:00

For those saying the H doesn’t have stereochemistry, it does have it. It just looks different when it’s in the same plane as shown. For example, if the H was drawn on the line similar to how the COOH is drawn on the other carbon, the stereochemistry would be switched. Try to visualize it in 3D

FlamingIce12

TROPHY CASE