Any insight for Automotive Sensor Inputs/ Front-End Protection.
in [Design]
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From: Joerg on 28 Apr 2010 19:01 Jim Thompson wrote: > On Wed, 28 Apr 2010 11:33:00 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Wed, 28 Apr 2010 18:09:18 +0100, John Devereux >>> <john(a)devereux.me.uk> wrote: >>> >>>> Johnny5 <dirtylogicdesigns(a)gmail.com> writes: >>>> >>>>> On Apr 26, 6:35 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- >>>>> Web-Site.com> wrote: >>>>>> On Mon, 26 Apr 2010 16:18:05 -0700, Joerg <inva...(a)invalid.invalid> >>>>>> wrote: >>>>>> >>>>>>> Jamie wrote: >>>>>>>> Johnny5 wrote: >>>>>>>>> I was curious if anyone had any insight into protecting an Opto- >>>>>>>>> isolator LED input from load dump, Jumpstarts, and many of the other >>>>>>>>> signals in the auto environment. FETS,CLIPPERS,Clamps? >>>>>>>>> Thank you in advance, >>>>>>>>> It is an open drain SSR. >>>>>>>> TVS diodes. Transorbs is another name for them. >>>>>>> Also Transzorb. And ST calls them Transil. It's trade names, like >>>>>>> Kleenex or Kim Wipes. >>>>>>> [...] >>>>>> No canned answers. It depends on the circuitry. >>>>>> >>>> [...] >>>> >>>>> Thank you all for the input, a little more on the circuit . Sensors >>>>> are pressure switches/Temp that are connected to Vbatt. Pressure High= >>>>> relay that switches Vbatt on/off. No current Limit. So I was thinking >>>>> it would be best use opto. HSR312 SSR, Vr=7v, Vf=1.6V , control >>>>> current approx 2mA. >>>>> >>>>> >>>>> Automotive opto front end for Vbatt switched with no current limit >>>>> >>>>> Bav99/ TVS with a current limiter suffice? ? >>>>> polarity protection p channel fet as well? any choice on fet, dmos >>>>> only? >>>>> thks >>>> Do you actually need to do anything? LEDS will survive brief overcurrent >>>> just fine. If you size the LED resistor for 12V operation near the 2mA, >>>> you will have to get up to 100V or so to even get to its rated 25mA >>>> maximum. Any such pulses will be very brief, the LED won't mind. >>>> >>>> I would just use a series resistor and connect a signal diode in >>>> anti-parallel across the LED. >>> There you go! >>> >>> So many posters here want to make simple problems difficult... TVS's, >>> etc :-] >>> >> Those posters tend to design reliable electronics :-) > > Nonsense! Find a single one of my chip designs that's ESD > sensitive... including those I designed in the '60's. > Can you give me part number, price and distributor (_with_ reel stock) of a Jim Thompson open drain SSR? >> Figure 1, for a dose of reality: >> http://www.automotivedesignline.com/howto/205101011 > > Learn to read. Particularly my automotive patents. Not a single TVS > in sight. > What has this thread to do with your automotive patents? Us guys have to use what's in stock here and now, not what's on a patent or what a company uses proprietarily. Because the client's purchasers have to be able to buy it. We can't bake ourselves a new chip every time we find that one is sub-par (and a lot of chips are). It is occasionally cheaper to just plop down a TVS ;-) >> Usually an LED survives that. But sometimes, especially when dumps >> happen in rapid succession, it doesn't. I don't have too much experience >> with automotive stuff for passenger cars but I do with electronics for >> larger vehicles such as aircraft. There, a non-TVS design is most likely >> going to hit the fan before it ever sees its fuselage mounting spot. At >> the RTCA test lab. > > Circuits should be designed from the outset to survive. After-the-fact > patches, like TVS's, are for amateurs :-) > Seems like you haven't designed such stuff for aerospace yet. Example: How is a PWM chip that only comes in a 40V edition supposed to survive an RTCA/DO-160 surge on a 28V supply rail? Yeah, you can make an over-voltage cutout around an n-channel plus half a dozen other parts. The smart and frugal engineer does that with one resistor and one TVS, to the tune of about 15 cents grand total. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jamie on 28 Apr 2010 19:37 Jim Thompson wrote: > On Wed, 28 Apr 2010 18:09:18 +0100, John Devereux > <john(a)devereux.me.uk> wrote: > > >>Johnny5 <dirtylogicdesigns(a)gmail.com> writes: >> >> >>>On Apr 26, 6:35 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- >>>Web-Site.com> wrote: >>> >>>>On Mon, 26 Apr 2010 16:18:05 -0700, Joerg <inva...(a)invalid.invalid> >>>>wrote: >>>> >>>> >>>>>Jamie wrote: >>>>> >>>>>>Johnny5 wrote: >>>>>> >>>>>>>I was curious if anyone had any insight into protecting an Opto- >>>>>>>isolator LED input from load dump, Jumpstarts, and many of the other >>>>>>>signals in the auto environment. FETS,CLIPPERS,Clamps? >>>>>>>Thank you in advance, >>>>>>>It is an open drain SSR. >>>>>> >>>>>>TVS diodes. Transorbs is another name for them. >>>> >>>>>Also Transzorb. And ST calls them Transil. It's trade names, like >>>>>Kleenex or Kim Wipes. >>>> >>>>>[...] >>>> >>>>No canned answers. It depends on the circuitry. >>>> >> >>[...] >> >> >>>Thank you all for the input, a little more on the circuit . Sensors >>>are pressure switches/Temp that are connected to Vbatt. Pressure High= >>>relay that switches Vbatt on/off. No current Limit. So I was thinking >>>it would be best use opto. HSR312 SSR, Vr=7v, Vf=1.6V , control >>>current approx 2mA. >>> >>> >>>Automotive opto front end for Vbatt switched with no current limit >>> >>> Bav99/ TVS with a current limiter suffice? ? >>> polarity protection p channel fet as well? any choice on fet, dmos >>>only? >>>thks >> >>Do you actually need to do anything? LEDS will survive brief overcurrent >>just fine. If you size the LED resistor for 12V operation near the 2mA, >>you will have to get up to 100V or so to even get to its rated 25mA >>maximum. Any such pulses will be very brief, the LED won't mind. >> >>I would just use a series resistor and connect a signal diode in >>anti-parallel across the LED. > > > There you go! > > So many posters here want to make simple problems difficult... TVS's, > etc :-] > > ...Jim Thompson Lets see. Series resistor and diode = 2 components TVS diode = 1 component and they come in bi or unidirectional. Hmm.
From: Jim Thompson on 28 Apr 2010 19:50 On Wed, 28 Apr 2010 16:01:29 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Jim Thompson wrote: >> On Wed, 28 Apr 2010 11:33:00 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >>> Jim Thompson wrote: >>>> On Wed, 28 Apr 2010 18:09:18 +0100, John Devereux >>>> <john(a)devereux.me.uk> wrote: >>>> >>>>> Johnny5 <dirtylogicdesigns(a)gmail.com> writes: >>>>> >>>>>> On Apr 26, 6:35 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- >>>>>> Web-Site.com> wrote: >>>>>>> On Mon, 26 Apr 2010 16:18:05 -0700, Joerg <inva...(a)invalid.invalid> >>>>>>> wrote: >>>>>>> >>>>>>>> Jamie wrote: >>>>>>>>> Johnny5 wrote: >>>>>>>>>> I was curious if anyone had any insight into protecting an Opto- >>>>>>>>>> isolator LED input from load dump, Jumpstarts, and many of the other >>>>>>>>>> signals in the auto environment. FETS,CLIPPERS,Clamps? >>>>>>>>>> Thank you in advance, >>>>>>>>>> It is an open drain SSR. >>>>>>>>> TVS diodes. Transorbs is another name for them. >>>>>>>> Also Transzorb. And ST calls them Transil. It's trade names, like >>>>>>>> Kleenex or Kim Wipes. >>>>>>>> [...] >>>>>>> No canned answers. It depends on the circuitry. >>>>>>> >>>>> [...] >>>>> >>>>>> Thank you all for the input, a little more on the circuit . Sensors >>>>>> are pressure switches/Temp that are connected to Vbatt. Pressure High= >>>>>> relay that switches Vbatt on/off. No current Limit. So I was thinking >>>>>> it would be best use opto. HSR312 SSR, Vr=7v, Vf=1.6V , control >>>>>> current approx 2mA. >>>>>> >>>>>> >>>>>> Automotive opto front end for Vbatt switched with no current limit >>>>>> >>>>>> Bav99/ TVS with a current limiter suffice? ? >>>>>> polarity protection p channel fet as well? any choice on fet, dmos >>>>>> only? >>>>>> thks >>>>> Do you actually need to do anything? LEDS will survive brief overcurrent >>>>> just fine. If you size the LED resistor for 12V operation near the 2mA, >>>>> you will have to get up to 100V or so to even get to its rated 25mA >>>>> maximum. Any such pulses will be very brief, the LED won't mind. >>>>> >>>>> I would just use a series resistor and connect a signal diode in >>>>> anti-parallel across the LED. >>>> There you go! >>>> >>>> So many posters here want to make simple problems difficult... TVS's, >>>> etc :-] >>>> >>> Those posters tend to design reliable electronics :-) >> >> Nonsense! Find a single one of my chip designs that's ESD >> sensitive... including those I designed in the '60's. >> > >Can you give me part number, price and distributor (_with_ reel stock) >of a Jim Thompson open drain SSR? All of my standard parts are listed on my website. OEM parts are listed by function but have no public part number. As for SSR's, I've designed only two types... one type on Hubble, one type on a Honeywell Satellite Division spinner/launcher... you know, get them up there, spin, then boom, blow bolts. Nary EVER a failure :-) > > >>> Figure 1, for a dose of reality: >>> http://www.automotivedesignline.com/howto/205101011 >> >> Learn to read. Particularly my automotive patents. Not a single TVS >> in sight. >> > >What has this thread to do with your automotive patents? Us guys have to >use what's in stock here and now, not what's on a patent or what a >company uses proprietarily. Because the client's purchasers have to be >able to buy it. We can't bake ourselves a new chip every time we find >that one is sub-par (and a lot of chips are). > >It is occasionally cheaper to just plop down a TVS ;-) > > >>> Usually an LED survives that. But sometimes, especially when dumps >>> happen in rapid succession, it doesn't. I don't have too much experience >>> with automotive stuff for passenger cars but I do with electronics for >>> larger vehicles such as aircraft. There, a non-TVS design is most likely >>> going to hit the fan before it ever sees its fuselage mounting spot. At >>> the RTCA test lab. >> >> Circuits should be designed from the outset to survive. After-the-fact >> patches, like TVS's, are for amateurs :-) >> > >Seems like you haven't designed such stuff for aerospace yet. Example: >How is a PWM chip that only comes in a 40V edition supposed to survive >an RTCA/DO-160 surge on a 28V supply rail? Yeah, you can make an >over-voltage cutout around an n-channel plus half a dozen other parts. >The smart and frugal engineer does that with one resistor and one TVS, >to the tune of about 15 cents grand total. I was designing for aerospace whilst you were still in knickers :-) Check the facts before you burp. ...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 | The only thing bipartisan in this country is hypocrisy
From: Joerg on 28 Apr 2010 20:11 Jim Thompson wrote: > On Wed, 28 Apr 2010 16:01:29 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Wed, 28 Apr 2010 11:33:00 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >>>>> On Wed, 28 Apr 2010 18:09:18 +0100, John Devereux >>>>> <john(a)devereux.me.uk> wrote: >>>>> >>>>>> Johnny5 <dirtylogicdesigns(a)gmail.com> writes: >>>>>> >>>>>>> On Apr 26, 6:35 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My- >>>>>>> Web-Site.com> wrote: >>>>>>>> On Mon, 26 Apr 2010 16:18:05 -0700, Joerg <inva...(a)invalid.invalid> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Jamie wrote: >>>>>>>>>> Johnny5 wrote: >>>>>>>>>>> I was curious if anyone had any insight into protecting an Opto- >>>>>>>>>>> isolator LED input from load dump, Jumpstarts, and many of the other >>>>>>>>>>> signals in the auto environment. FETS,CLIPPERS,Clamps? >>>>>>>>>>> Thank you in advance, >>>>>>>>>>> It is an open drain SSR. >>>>>>>>>> TVS diodes. Transorbs is another name for them. >>>>>>>>> Also Transzorb. And ST calls them Transil. It's trade names, like >>>>>>>>> Kleenex or Kim Wipes. >>>>>>>>> [...] >>>>>>>> No canned answers. It depends on the circuitry. >>>>>>>> >>>>>> [...] >>>>>> >>>>>>> Thank you all for the input, a little more on the circuit . Sensors >>>>>>> are pressure switches/Temp that are connected to Vbatt. Pressure High= >>>>>>> relay that switches Vbatt on/off. No current Limit. So I was thinking >>>>>>> it would be best use opto. HSR312 SSR, Vr=7v, Vf=1.6V , control >>>>>>> current approx 2mA. >>>>>>> >>>>>>> >>>>>>> Automotive opto front end for Vbatt switched with no current limit >>>>>>> >>>>>>> Bav99/ TVS with a current limiter suffice? ? >>>>>>> polarity protection p channel fet as well? any choice on fet, dmos >>>>>>> only? >>>>>>> thks >>>>>> Do you actually need to do anything? LEDS will survive brief overcurrent >>>>>> just fine. If you size the LED resistor for 12V operation near the 2mA, >>>>>> you will have to get up to 100V or so to even get to its rated 25mA >>>>>> maximum. Any such pulses will be very brief, the LED won't mind. >>>>>> >>>>>> I would just use a series resistor and connect a signal diode in >>>>>> anti-parallel across the LED. >>>>> There you go! >>>>> >>>>> So many posters here want to make simple problems difficult... TVS's, >>>>> etc :-] >>>>> >>>> Those posters tend to design reliable electronics :-) >>> Nonsense! Find a single one of my chip designs that's ESD >>> sensitive... including those I designed in the '60's. >>> >> Can you give me part number, price and distributor (_with_ reel stock) >> of a Jim Thompson open drain SSR? > > All of my standard parts are listed on my website. OEM parts are > listed by function but have no public part number. > > As for SSR's, I've designed only two types... one type on Hubble, one > type on a Honeywell Satellite Division spinner/launcher... you know, > get them up there, spin, then boom, blow bolts. Nary EVER a failure > :-) > See, no publicly available SSR from your desk. Now where does that leave the OP? BTW, my stuff with TVSes in there doesn't fail either. And it's really low cost :-) >> >>>> Figure 1, for a dose of reality: >>>> http://www.automotivedesignline.com/howto/205101011 >>> Learn to read. Particularly my automotive patents. Not a single TVS >>> in sight. >>> >> What has this thread to do with your automotive patents? Us guys have to >> use what's in stock here and now, not what's on a patent or what a >> company uses proprietarily. Because the client's purchasers have to be >> able to buy it. We can't bake ourselves a new chip every time we find >> that one is sub-par (and a lot of chips are). >> >> It is occasionally cheaper to just plop down a TVS ;-) >> >> >>>> Usually an LED survives that. But sometimes, especially when dumps >>>> happen in rapid succession, it doesn't. I don't have too much experience >>>> with automotive stuff for passenger cars but I do with electronics for >>>> larger vehicles such as aircraft. There, a non-TVS design is most likely >>>> going to hit the fan before it ever sees its fuselage mounting spot. At >>>> the RTCA test lab. >>> Circuits should be designed from the outset to survive. After-the-fact >>> patches, like TVS's, are for amateurs :-) >>> >> Seems like you haven't designed such stuff for aerospace yet. Example: >> How is a PWM chip that only comes in a 40V edition supposed to survive >> an RTCA/DO-160 surge on a 28V supply rail? Yeah, you can make an >> over-voltage cutout around an n-channel plus half a dozen other parts. >> The smart and frugal engineer does that with one resistor and one TVS, >> to the tune of about 15 cents grand total. > > I was designing for aerospace whilst you were still in knickers :-) > > Check the facts before you burp. > Then you should be intimately familiar with DO160. Yet you haven't answered the question above, how you would solve that situation for 15c or less without a TVS. How did the Romans say? Hic Rhodos, hic salta. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jim Thompson on 28 Apr 2010 20:26
On Wed, 28 Apr 2010 17:11:18 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Jim Thompson wrote: [snip] >> >> I was designing for aerospace whilst you were still in knickers :-) >> >> Check the facts before you burp. >> > >Then you should be intimately familiar with DO160. Yet you haven't >answered the question above, how you would solve that situation for 15c >or less without a TVS. > >How did the Romans say? Hic Rhodos, hic salta. That'd be _way_ after my time in aerospace. What is it you have running in any space vehicle? What is it you have running in any car electronics? Perhaps you have something in an implant. I do. ...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 | The only thing bipartisan in this country is hypocrisy |