12V Switching Car PSU by UC3843 + 74LS02

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Here is circuit power supply switching 12V. For Car PSU use IC UC3843 and mosfet IRFZ44N.
It is nice circuit for electronics PC MP3 Player. System control by digital circuit IC 74LS02

The next version will be much like the V2, except for a few changes:

* Added a trimmer (R13) to the R8/R9 voltage divider so it’s easy to get the exact voltage wanted and you don’t have to change components to get another output voltage.
* Redone the PCB to fit the smaller low-imp caps that are about 2/3’s the size of the original electrolytes I got a hold of (at Elfa, the stock number is 67-183-32 ).
* Added a 5V regulator to allow the GPS receiver (or headunit) to stay on, even when the computer is off.
* Added a low power on/off switch to the PSU so it’s easy to control from a computer, the car should toggle the PSU on when the ignition is turned on, the computer should turn it off when pulling the off contact high while the car ignition wire is off. The +12v car ignition signal should also be conditioned so it’s suitable for a 5v input on a CPU and made available, the standby current is around 30mA, which I hope is low enough.

State Car [On] PC [Off] Output
Running 1 X On
Shutting down/off 0 0 No change, NOT OFF
Turn off (short) 0 1 Off

Read More Source:
http://dion.swamp.dk/carpower.html
Thank you.

This entry was posted on Tuesday, November 27th, 2007 at 11:23 pm and is filed under Automotive, switching power supply. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.