unknown LED Driver IC

[davenn]

hi gang

got all these LED chasers. The flamin' manufacturer's scrapped the IC # off the chip

its a 4pin DIL (ie. the same as a 555 timer) google searches turned up lots of PIC driven LED chasers. Wonder if this is a PIC or some other linear IC anyone come across a cct like this ?

Cheers
Dave

 

[hexreader]

I would be fairly confident that this is a PIC microcontroller.

Probably PIC12F629.

Possibly PIC12F675.

Possibly PIC12F683.

Be aware that a replacement PIC would need to be programmed before it will do anything.

Hope this helps

 

[davenn]

hey mate

yeah the 12F629 seems a reasonable candidate even has the correct pins for power supply

I mite unsolder one out of cct and see if I can read the firmware. That if they havent set the code to stop the reading of the chip. worth a crack at it

thanks
Dave

 

[(*steve*)]

Unlikely to be a PIC given the way the inductor is connected. (that's assuming the inductor is used to boost the incoming voltage)

 

[davenn]

Unlikely to be a PIC given the way the inductor is connected. (that's assuming the inductor is used to boost the incoming voltage)

ok any thoughts on what else it mite be ?
I dont know of any specific LED driver chips googling such just provided lots of links to PIC drivers

Dave

 

[(*steve*)]

Looking at that circuit again, I can't see that it could be a boost regulator. Maybe the inductor forms part of a filtering circuit. If it does, then I guess it could be a PIC.

But it seems unusual to have an inductor there... And the resistor across the incoming power supply... Weird.

 

[davenn]

........ And the resistor across the incoming power supply... Weird.

yeah why the hell would you hang a 560 Ohm across the supply ??

who knows


D

 

[duke37]

Is that a Zener diode or just an ordinary diode acting as a freewheel?
It looks suspiciously like a voltage convertor to me, earthing the inductance to get sufficient current and then dumping it into the leds, Cunning.

 

[MagicMatt]

I'm sure that's a PIC, as they have the MCLR pin pulled up. Each pin can usually drive 20-25mA which is enough to drive a single LED.

The program on the PIC is likely to be VERY simplistic, just cycling turning one bit on a register, but you'd need a cheap programmer.

I can't recall exactly where I've seen that config before, but it was to do with driving LEDs from a coin cell, so I agree it's probably a booster of some sort.