True, but before they had any reverse polarity protection in there they didn't have an inrush limiter either. So they could just use a big enough p-channel FET. The usual cheapo inrush limiter is ... the battery cable.
If you have two FETs, yes. With only one, no.
[...]-- Regards, Joerg http://www.analogconsultants.com/
Cheapskate ;-) ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 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.
No kidding, in the last 2-3 years I found the number of clients and projects where cost really matters to be noticeably on the increase.
-- Regards, Joerg http://www.analogconsultants.com/
I'm seeing that as well. Everyone wants a chip with no external components... which usually means a "shoot-yourself-in-the-foot" incident... chip size grows and power-MOS on-chip becomes a heat issue :-( ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 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 may some day need one as well. In the not too distant future as they say. But not for cost reasons, it'll be for space reasons.
-- Regards, Joerg http://www.analogconsultants.com/
You uttered:
Hint: you can soft start by slowly ramping the gate voltage of the fet. However, you said that should never be done. I disagree. In fact, such circuitry is the basis of hot swapping.
Haven't you learned yet not to argue with me?
^^^^^^^^^^^^^^^^^
As in "not the FET".
Then go ahead and do it. But please not in any mission-critical gear such as aerospace or medical.
When you have a brown-out situation or an erratic contact the FET will continuously go through it's linear region for the diode drop range, over and over again. Gets hot. Then one fine day ... *PHUT*
When I get into a cantankerous mode I like to argue :-)
-- Regards, Joerg http://www.analogconsultants.com/
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