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All power devices are conveniently mounted on one side of the PCB.ĭisclaimer - All work, schematics, notes, hardware, are not guaranteed and up to you to verify their correctness. HEAT SINK ALL POWER TRANSISTORS AND THE REQULATOR! For testing, small heat sinks will work for a while, but you will eventually toast the output drivers. Read the LM1949 Data sheet for its specific operations. Also if you don't want to use the opto-isolators, just drive the input of the LM1949 off of Pin 3 of the isolator, and use the power ground instead of the control ground. The pads can also be used to power another board if needed (check power dissipation on LM2940). Pads exist for direct 5v connection, and are labeled. If you are running of a clean regulated 5v supply, it doesn't need to be stuffed.

Most of the power supply parts are non-critical. Also and extra component pad was added at the last minutes near R17-R20 for a noise cap if desired. Most small caps are axial ceramic Z5U or X7R and of 50V ratings. The TVS will be much more costly however. Z1-Z4 uses 1N5364 for injectors or can use a TVS of similar ratings. Most parts are purchased from digi-key or mouser (except for the LM1949, IGBT). If using the IGBT for injectors, leave C20, C21, C22, C23, as they control some small output oscillations, I think they can be removed when driving ignition coils, but no harm will be had if they are left in. Add clamp zener 1-4 for injector drivers only. If using TIP121 (or better) for injectors, remove C20, C21, C22, C23, change R9, R10, R11, R12 to 0 ohm jumpers, C5, C6, C7, C8 to 0.01uF. When using as ignition drivers, the peak hold function is not used, so leave C16-C19 open. C16, C17, C18, C19 Determine Peak Hold Delay, If open, no peak hold function.

For Ignition, 8 amp, use Rx=100 Ry=33, Sense resistor of 0.05 ohm. For 4 Amp Peak, 1 Hold (Injectors), use Rx=0, Ry=Open, Sense resistor 0.1ohm.

Minor component changes will result in the Injector driver with no layout changes. Highlighted Designators indicate changes between Ignition and Injector driver parts