Any insight for Automotive Sensor Inputs/ Front-End Protection.
in [Design]
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From: Johnny5 on 26 Apr 2010 20:00 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. > > ...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 athttp://www.analog-innovations.com| 1962 | > > The only thing bipartisan in this country is hypocrisy 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
From: Jim Thompson on 26 Apr 2010 20:13 On Mon, 26 Apr 2010 16:57:30 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Jim Thompson wrote: >> On Mon, 26 Apr 2010 16:18:05 -0700, Joerg <invalid(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. >> > >Sure it does. But it ain't rocket science. There must be a resistor, >then a TVS to GND, then another resistor, then LED to GND. The latter >resistor is sometimes part of the SSR already. > >Hey, anyone else have issues with a Digikey order today? I was on the >phone with their IT for over an hour, they were becoming frustrated as >well, still no answer what's wrong. Had to order at Mouser now. Who the frick needs a TVS? ...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 26 Apr 2010 20:19 Jim Thompson wrote: > On Mon, 26 Apr 2010 16:57:30 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Mon, 26 Apr 2010 16:18:05 -0700, Joerg <invalid(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. >>> >> Sure it does. But it ain't rocket science. There must be a resistor, >> then a TVS to GND, then another resistor, then LED to GND. The latter >> resistor is sometimes part of the SSR already. >> >> Hey, anyone else have issues with a Digikey order today? I was on the >> phone with their IT for over an hour, they were becoming frustrated as >> well, still no answer what's wrong. Had to order at Mouser now. > > Who the frick needs a TVS? > Entirely depends on the SSR. If it's a 12V input version and abs max sez you'd be gitten a *PHUT* sound at 30V you better put somethin' in there :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Robert Baer on 27 Apr 2010 05:04 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. Do not forget protection from 48V nad reverse polarity!
From: Fred Bartoli on 27 Apr 2010 05:13
Joerg a �crit : > Jim Thompson wrote: >> On Mon, 26 Apr 2010 16:18:05 -0700, Joerg <invalid(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. >> > > Sure it does. But it ain't rocket science. There must be a resistor, > then a TVS to GND, then another resistor, then LED to GND. The latter > resistor is sometimes part of the SSR already. > Ah, you don't directly clamp the battery voltage? Too bad, that would have been another psshhh pop phuttt time... Well, maybe not that long :-) -- Thanks, Fred. |