General Purpose Low Level Ignition Drive

[jharvey]

I like these "NGP15N41CLG".

Have you seen IRGB14C40LPBF

[Dan]

I like these "NGP15N41CLG".

Have you seen IRGB14C40LPBF

Nope, but I definately like the look of it as well.

[jharvey]

Yeah that chip has a good reference in the StingrayIII design, very simple to use.

[Costa]

Went searching for the BOSCH BIP373 online. They seems to be hard to get.
Only Future Electronics lists them, but show zero stock.
http://www.futureelectronics.com/en/Tec ... SCH9385691

It looks like DIYAutotune is the only place to get BIP373's.

[Fred]

Went searching for the BOSCH BIP373 online. They seems to be hard to get. :(
Only Future Electronics lists them, but show zero stock.
http://www.futureelectronics.com/en/Tec ... SCH9385691

It looks like DIYAutotune is the only place to get BIP373's.

Yeah, that has always been the case! There are better options available anyway, so no bother :-)

[preludelinux]

I got these to replace bips373's - ISL9V3040P3. I would think most dont want to pay $8 for each bips363. I have 12 of them.

http://www.fairchildsemi.com/ds/IS/ISL9V3040P3.pdf

[jharvey]

Note fig 5 (missing the label) shows the min voltage drop will be .7 volts or so, and could be as high as 1.5 volts at 5 amps. At 5 amps and 1 volt, that's 5 watts of resistance heating to deal with. Using a MOSFET for a general purpose low side drive will dissipate much less heat. With this device you'll want to have a large heat sink.

[Fred]

Sorry Jared, but the above is bad advice! Ignition drives require circa 400V capability or the spark produced will be shit. MOSFETs to do that are made of a rare and expensive variety of unobtainium. Furthermore, in terms of coil performance, current flow matters, not absolute voltage, so the 1.5V loss is acceptable, and better than an average ignitor. Unfortunately heat is a fact of life for ignition drivers, ALL OEM ones are heatsinked extensively, and MOST are in the engine bay. If you want something free of heat, get points :-)

I read over the spec of those drivers and advised prelude in IRC last night. Due to their extremely favourable gate characteristics, driving them with a 25mA max line driver and 200 ohm current limit resistor is acceptable to gain good switching performance. Just for the record. Nice little units! :-) Please, mount them in the engine bay, though, not in the ECU :-/

[jharvey]

Sorry about that. I read it as low level drive, not low level ignition drive. Fred is correct the higher voltage changes things for ignition. It changes the dwell, such they they are not on full time, ect.

[Fred]

Lower voltage prevents rapid collapse of the field and lowers essential output voltage from the coil to the plug making it harder for it to jump the gap and ignite the mix. See other thread for sorry in reverse direction :-/