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Old Nov 06, 2011, 12:24 AM
PLD
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PLD-ESJ100A / HV: 100A on/off power switch. Avoid sparks and be safe!

I've been skirting around this product for a long time, a few people have asked for it but really it's a big of a "without a home" product idea.

Here's the features:
  • 100A switching capability (200A peak)
  • 30V rated for the non-HV, 50V rated for the HV edition
  • Tiny losses, only 5W @ 100A (you lose more in your connectors!)
  • Inherently suppression of sparks when connecting
  • Remote on/off switch using small toggle or slider
  • Onboard LED for power-on/off status
  • External LED for power-on/off status
  • Quad MOSFETs for failover safety
  • Design biased to keep power ON
  • Switch voltage drop sense port / current measure port
  • Easy 4 point mounting
  • Less than 2x2" board sizes
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Last edited by PLD; Nov 07, 2011 at 09:16 AM.
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Old Nov 07, 2011, 09:15 AM
PLD
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Tonight I've created and submitted a "High Voltage" version that'll cope with up to 50V (so, basically 10S is safe) and 100A. It's beefier than the 30V version due to the much larger MOSFETs required.
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Old Nov 07, 2011, 08:05 PM
Chillaxin dude!
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how about magnetic reed switching for on/off?
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Old Nov 07, 2011, 08:18 PM
PLD
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If you use a latching reed, you can do it - however if you use a normal reed/magnet method then you'll need a bunch of more advanced electronics to simulate the latching.

What would be driving the need for a reed/concealed switch that drives 100A ? Trying to get something super-slippery ?
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Old Nov 07, 2011, 08:20 PM
PLD
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Was just thinking a bit more about this, technically a standard reed could work on this unit because of the way that the design relies on things being "open", but to switch it off (and keep it off) you'd have to find a way to keep the magnet in place.
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Old Nov 07, 2011, 08:30 PM
Chillaxin dude!
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Newcastle, NSW, Australia
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checkout the EMCOTEC high current switches. They use them for marine use. The on/off switch is a socket that takes a magnetic cap, removed for ON condition.

http://www.hkm-models.com/Emcotec%20Switches.html

Will remove this if you want Paul... was just trying to be helpful...
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Last edited by BulletMaster; Nov 07, 2011 at 08:35 PM. Reason: thought about it...
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Old Nov 07, 2011, 08:45 PM
PLD
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That's pretty much what I'm competing with, on most of their products.

Downside here is I can't yet get to have nice switch bodies like what they have (no doubt they dumped a few thousand to get those made / patented ). They do have a great packaging setup, something I'm trying to work towards.

Knowing what I know about the state of MOSFET technology, I think they're pulling from the manufacturer datasheets (and they can just point to them when any one asks). Sorely tempted to do similar at times, if only to make parallel comparisons.

eg, the PLD-ESJ-100A uses 4 x 1.5mR MOSFETs, giving 0.375mR, or just short of 4W dissipation at 100A for the whole board (1W per MOSFET). On the other hand, if I rated it based on what it could survive then I could just drop to 1 MOSFET and let it handle the 4W outright - but it'd be marginal.

The ESJ100A-HV uses only 3 x 1.5mR MOSFETs but they're substantially larger and could cope with 5W each without a problem, again, I could just drop to 1 MOSFET and let it go at that, but I hate the idea that when people run these things at the stated limits that it's "marginal".

Ugh, ethics...
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Old Nov 11, 2011, 04:33 PM
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Daniel. Have noidea about electronics but whats the difference between this device and the ones already in use using a Bt555?
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Old Nov 11, 2011, 06:02 PM
PLD
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Elossam, do you have a link to the Bt555 ?
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Old Nov 12, 2011, 05:02 PM
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The right name is BTS 555 Here you have some links to the data sheet.
http://www.datasheetcatalog.com/data...5/BTS555.shtml
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Old Nov 12, 2011, 06:58 PM
PLD
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Okay I took a look at the BTS555 device, I've certainly seen those things before. They ultimately do the same core job, switching a lot of current, though the BTS555 has a lot of other stuff thrown in on it such as being able to use it as a high-side device and it has reverse polarity protection.

The downside is that to really switch 100A you would need at least 2 or 3 of them. At 2.5mR, if you were trying to manage 100A, that'd be a hefty 25W dissipated, that's okay if you have the room to have a large heatsink, but in this case it's just not practical.

The combined resistance of the MOSFETs I'm using here are about 0.5mR, which drops the 100A dissipation down to only 5W, which can be handled by the MOSFETs and PCB directly without extra heatsinking.

Paul.
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Old Nov 13, 2011, 03:55 PM
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Ok. In any way we don't trust on the 555 but use the initial load through a resistsnce to "slow" charge the capacitorss wich should be the responsible of the spark. Maybe not as comfortable as a switch usebut more reliable not having components along the power line while flying. The system you designed allows a close circuit in case of any component failure?
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Old Nov 13, 2011, 05:32 PM
PLD
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Elossam, the ESJ units I design build fall to "on" by default, and with the multiple MOSFETs on these 100A unit devices, because it's over-engineered, if one of the MOSFETs fail (closed or open) the others can still carry the current.

Regarding the sparking, I'll be using a slightly slower turn-on for the gates which will prevent the sudden inrush.

Paul.
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Old Nov 13, 2011, 07:09 PM
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Daniel this seems like a good candidate for upcoming project..
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Old Nov 13, 2011, 07:37 PM
PLD
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Nelapaty, where were you thinking of incorporating the 100A switch?
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