eod

electronics/readme.md

@@ -203,3 +203,35 @@ I also did a test with a brass GIK and another bullet connector (this was before
   - make a stepper motor board and connect the two together (maybe with an opto-isolated serial connection?)
     - or… just use the tabletop instron… or better yet, the Desktop EDM!
 - pretty soon I'm also going to have to start worrying about a constant source or clean DI water. For these little tests I can just squirt some in a beaker but that won't work for long given how hazy the water gets after just a few minutes of constant burning.
+
+
+- After frying another gate driver (the discharge one) during testing, it seems like the circuit could use a little more protection. I may need to include negative voltage protection on the source of the MOSFET's
+  - like this: (from http://www.ti.com/lit/ml/slua618/slua618.pdf)
+  - this one looks good: [DFLS1150](https://www.diodes.com/assets/Datasheets/ds30593.pdf)
+
+<img src="images/negative_voltage_protection.png" width="300px">
+
+
+
+#### PMOS Re-Design?
+
+- NMOSFET to drive PMOS gate: [3.3v logic compatible and Vds up to 100V](https://www.digikey.com/product-detail/en/infineon-technologies/IRLML0100TRPBF/IRLML0100TRPBFCT-ND/2202230)
+
+After simulating a P-MOS circuit, I'm finding that there's an excessive amount of loss in the level shifting circuit. In order to switch the gate as quickly as I would like, I found that those resistors need to be on the order of 1kohm (or less). With a 100V supply, this is ~10W of dissipation whenever I want to open the gate. Not ideal...
+
+There may be a way around this with totem-pole drivers but I haven't wrapped my head around that yet.
+
+This got me back to thinking whether I could just provide my own charge-pumped boost voltage to the gate driver so I don't have to rely on it's little trickle of current. I simulated a 555 version of this but am finding that I get the same problem that I was having with the bootstrap circuits: the capacitor who
+
+[this appears to be one way to do it... but it confuses me](http://www.irf.com/technical-info/designtp/dt92-4.pdf)
+
+or do a radical redesign with logic level high voltage mosfets
+
+​	like this: [NTP60N06L](http://www.onsemi.com/pub/Collateral/NTP60N06L-D.PDF) (60V, 60Amp, Vgth = 1.5V)
+
+[This guy appears to be asking the same question I am](https://www.eevblog.com/forum/projects/diy-programmable-dual-channel-bench-psu-0-50v3a/msg664832/#msg664832). This is the circuit he came up with:
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+<img src="images/cpump_v3.png">
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+or use [isolated dc/dc converter](https://www.digikey.com.au/product-detail/en/xp-power/IE0312SH/1470-1393-5-ND/4487774)....? (idea from [here](https://electronics.stackexchange.com/questions/151428/floating-charge-pump-for-high-side-n-channel-mosfet-bias))
+