Yep, extremely low power, switcher start-up circuitry, and I certainly do have ideas of my own: controlled surge, then, once switcher starts, auxiliary supply is turned off _completely_, no capacitor current at all... done with a readily available 15 cent part.
Students! What is the beginner's error in this...
Other than it being general Larkin crap ;-) ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
[snip]
their HV depletion mode FET technology- they've been on the market for years, they're pretty rugged and impervious to hellacious transients.
Depletion-mode FET was considered but, because this is derived before true DC, it has issues. But I still may use a depletion-mode FET as a control element. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
The shunt diode is redundant.
[snip]
Perhaps. Depends on the NMOS. There are other, more significant, problems. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I mentioned that.
-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Why do you actually never say anything?
-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
I guess I learned that technique from you ;-) ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Idiot. I posted a circuit. You haven't.
So, what's wrong with my suggestion? I suppose you don't understand it because it's not Spice-ready.
This is an electronics discussion group. So try discussing electronics.
-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
It's crap. Others have said so. It'll blow all to hell on the input surge.
I do, you don't. You just pimp yourself, but no one wants your ride ;-) ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Then engineer it so that it doesn't. A series line resistor, as I suggested in my original post, might be prudent. That's commonly done.
A negative surge is clamped by a forward-conducting diode. A positive surge dumps into the big cap; the C-ratio can be large. The fet, properly selected and driven, is pretty well protected against SOA violations. It's not hard to do this right. Some 2-cent mosfet will do just fine. [1]
So, are you going to use it?
If not, are you going to come up with an idea of your own? Or claim to, but refuse to reveal it?
Come on. Quit sniveling and say something substantive about electronics.
[1] a reverse recovery snap of the mosfet substrate diode is possible, but not likely a hazard. But worth at least considering.-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
It does the same as a single zener, but is more complex.
No, my circuit goes into zero dissipation mode when it doesn't need to charge the cap. The low-voltage shunt mosfet (or NPN) could be integrated into a controller chip. Maybe Jim can patent the idea.
-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Not really, the idea is to select the dropping cap to deliver only what you need and the excess is shunted via the NPN. Excess being no load or topped off battery after charge.
Your use of a mosfet in the same place being regulated in linear mode would also do the same, it could even oscillate if the ripple wasn't properly handled in the - feed back. I suppose one could use a buck switcher to reduce heat if that is an issue.
The charger I made didn't generate any heat that was even noticeable and that was with no heat sink. I don't suggest such designs due to their nature in design, they aren't that safe..
Jamie
Body diode?
Jamie
I ended up with this...
Using a depletion-mode NMOS FET.
I have a version I personally liked better that used a cheapy TRIAC under DDROP3, but I could not find a way to get some "free" power for the gate... needed while pumping, goes away when overcome by the switcher coming on line.
(This is a wild high PFC, high efficiency dude, where the customer is squeezing me for milliwatts :-) ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
As Spehro suggested, the fet can be turned on when the current swings negative, which shorts the body diode and improves efficiency a tiny bit more.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Yep, that's very similar to my 'heater pulse regulator' but if you want to shave the last mW out of it then you may want to add some form of hysteresis because, what happens is, after the initial charge up, bringing Vcc to 'reg', it then goes into 'series pass regulator' mode for the rest of the positive cycle. That may not be a problem for you because you're using the cap dropper, and I wasn't, but mine was regulating on the order of 9 watts and the 'series pass' bit was adding another 3.
I was using junk bin parts so rather than get too terribly fancy I just summed in a bit of the AC waveform so the MOSFET would be forced off after the charge up. That had the effect of a charge pulse twice per half cycle since it was 'in range' on the down slope as well as the up.
That's crazy. Not only is it expensive, once the 24 volt supply kicks in, it dissipates most of a watt, doing nothing.
Boy, did I just save you some embarassment.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
You're so ignorant you don't know how it works. Thanks for the exhibition! ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Well, how much power do R1, R2, the TL431, and ROFF dissipate once the main supply is up?
Harder question: what's the worst-case dissipation of the fet if the main supply doesn't come up, like if the load is shorted or something?
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Bwahahahahaha! You lost the thread... actually two threads... and a controller chip...
Follow your own advice... do your own searching ;-) ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
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