> manufacturer tell me they only supplied car manufacturers!
>
> I even tried another tack, look up devices in a distributors catalogue to
> ascertain what is available, get the data sheets and hope that one of the
> devices comes close, then order some. Guess what - Out of Stock, When are
> they getting more - Don't know, in fact we have never had any!
>
> The nearest I have come for my application is to use a driver from Micrel
> (minimum 100 pieces delivery 12 weeks) and a seperate N Channel Power FET.
>
> I'm not paranoid, they are really out to get me!
>
> Yours Frustratedly
>
> Chris Carr
>
>
> ----- Original Message -----
> From: "David Duffy" <spamBeGoneavdspamBeGoneUQ.NET.AU>
> To: <TakeThisOuTPICLISTEraseMEspam_OUTMITVMA.MIT.EDU>
> Sent: Saturday, August 12, 2000 1:49 PM
> Subject: [EE]: Protected High Side Driver
>
>
> > Thought someone on the list may have come across what I'm after.
> > I'm looking for some high-side driver IC's with the following

> >    30V Operation.
> >    1A Current source.
> >    Fault protected in case of shorted loads.
> >    4/8/16 Drivers per package.
> >    Serial (shift register) input would be great.
> >    SIL package for easy heatsinking.
> > This may be asking a lot be you just never know!
> > BTW, I will be driving them with a PIC.  :-)
> > Regards...
> > ___________________________________________
> > David Duffy        Audio Visual Devices P/L
> > U8, 9-11 Trade St, Cleveland 4163 Australia
> > Ph: +61 7 38210362   Fax: +61 7 38210281
> > New Web: http://www.audiovisualdevices.com.au
> > New email: RemoveMEavdTakeThisOuTaudiovisualdevices.com.au
> > ___________________________________________
> >
> > --
> > http://www.piclist.com hint: The PICList is archived three different
> > ways.  See http://www.piclist.com/#archives for details.
> >
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.

>My favorites are TI for this.  See
>http://www.ti.com/sc/docs/products/msp/control/index.htm
>
>Look under Power + Control ; Power + Logic ; Power + Arrays .
>
>For high-side switch, my best bet is you could only get the pre-FET
>type leaving you to tailor the Vgs voltage.
>
> >Thought someone on the list may have come across what I'm after.
>I'm looking for some high-side driver IC's with the following
>attributes;
>    30V Operation.
>    1A Current source.
>    Fault protected in case of shorted loads.
>    4/8/16 Drivers per package.
>    Serial (shift register) input would be great.
>    SIL package for easy heatsinking.
>
>David Duffy        Audio Visual Devices P/L

>David Duffy wrote:
>
>>Sounds simple(ish) & obvious!  Hmmm, why didn't I think of it?  :-)
>>I may be able to get away with a power resistor in series with the
>>supply line (between battery & drivers) to limit the current. A lamp
>>would work even better but can't afford an O/C filament to stop the
>>unit from working. The battery supply is 24Vdc and the unit will be
>>for firing fireworks "electric matches" or igniters by remote control.
>
>The fireworks / pyro control systems that my company manufactures does
>things a little differently: the channel 'arm' relay connects one side of
>the igniter to the high side of the battery.  A current sense FET (IRCZ24)
>is turned on when the channel is to be fired.  The current limit is set to
>about 6 amps or so.
>
>Both sides of the ignitor are shunted by the normally closed contacts of
>the arm relay while the channel is not armed.  In addition, both sides of
>the ignitor are floated above ground by a few volts and monitored to look
>for ground shorts or leakage.  Its kind of a bridge circuit - if something
>upsets the balance, that channel is locked out and a fault indication is
>sent back to master control.
>
>Each firing channel uses 3 sections of LM2901 quad comparitor (2 sections
>for the bridge and 1 section for continuity detector), 1 section of LM2904
>dual op-amp (FET driver / current limit), 1 section of NEC EPE series dual
>relay (great little dual 30 Amp SPDT relay), 1 IRCZ24 FET, and about 1/4 of
>a EPM7032SLC-44 epld from altera.  The epld does all the timing and serial
>communications as well as the fault / arm / fire logic required.
>
>In a nutshell, that is how I did our system.
>
>Look over your requirements carefully - there may be no need to use a high
>side driver.  It is dead simple to build a current limited low side driver
>using a sense FET and a single section of op-amp.  As a bonus, the op-amp
>takes care of level translation from your logic supply to the drive
>required for the FET.  The caveat is that you must control what happens
>with the high side supply.  My system monitors for faults before it allows
>the ignitor to be connected to the high side, but this requires an arm
>relay for each channel.  This is a tradeoff that I was happy to accept.

> Dwayne Reid wrote:
> >David Duffy wrote:
> >
> >>Sounds simple(ish) & obvious!  Hmmm, why didn't I think of it?  :-)
> >>I may be able to get away with a power resistor in series with the
> >>supply line (between battery & drivers) to limit the current. A lamp
> >>would work even better but can't afford an O/C filament to stop the
> >>unit from working. The battery supply is 24Vdc and the unit will be
> >>for firing fireworks "electric matches" or igniters by remote control.
> >
> >The fireworks / pyro control systems that my company manufactures does
> >things a little differently: the channel 'arm' relay connects one side of
> >the igniter to the high side of the battery.  A current sense FET

>Blue Smoke out of Calgary does something similar - they have 16 channels on
>each of 16 common lines for a total of 256 channels.  They can fire any or
>all of the 16 channels associated with each common line but can't fire
>channels that span multiple commons in the same instant.  Not much of a
>problem for fireworks shows.
>
>Just how many high side drivers do you need?  20?  How long is your firing
>pulse?  You might consider doing it the 'brute force' method - TIP32
>transistors with small emitter resistors and 2n4403 transistors doing the
>classic 2 transistor current limit.  If you limit your fire pulse duration,
>you don't need to worry about heatsinking the transistors.
>
>You will want to have monitoring to detect a shorted transistor.  This is
>simply having pull down resistors at the rail outputs and ensuring that
>there is no voltage present when the high side driver is supposed to be
>off.  Disable the ground (common) lines if there is a fault.
>
>You really should use relays for the ground switching.  This gives you the
>mechanical air gap that a lot regulations require and if you do wind up
>firing multiple channels simultaneously, they can handle the required
>current.  I'm quite partial to the T90 series from P&B as well as the EPE
>series from NEC.  The EPE relay is really nice - 2 fully independent SPDT
>30 Amp relays in a package about the same size as the T90.  I have welded
>the contacts on those, however, when a screwdriver fell onto the PCB and
>shorted out the current limit stages.  Again, fault detection is a good
>idea.  In my units, a fault at the relay disables the current limit drivers
>and a fault in the current limit drivers disables the relays.