User Configurable Single / Multi Mode 7135 drivers Mod

[kosPap]

As you know the lower right leg of the AMC7135 chip accepts a signal from the control chip to PWM the output and modes.
When one connects that leg with thebattery + the control chip is practically negated and the AMC7135 chips work full time

This mod allows the suer to switch between single and multi mode after the light is finished.

What I did was to make a channel for the user to send +current to the chip by bridging the contact with the center spring pad.

Process:
I located aplace on the driver to drill. It took quite an effort to place the hole properly cos right next to it run the -battery and -LED traces.
I started the hole with a very hot needle and then proceeded with 0.35 and 0.45mm drill bits

then I used some wire bend properly, and soldered

exit hole on the left and wire stub on the right

That's all

Note: there is a chance that getting the wire too hot while bridging will unsolder its other end too.
For this purpose I poted the drivers components with thermal epoxy to lock it in place....

 

[schizeckinosy]

I thought that you had made this unnecessarily complicated, but then I see that the idea is that it is user bridgeable while in the flashlight. You say this in the title but not in the post. Very cool!

 

[kosPap]

Fixed it! thanks!

 

[Illuminated]

Interesting...so, this might also work on the Qlite Rev.A 7135*8 driver?

I don't have one yet (enroute) to investigate.

Magnetic (or other) switch to change between single/multiple mode comes to mind...

Thanks for sharing this.

John

 

[kosPap]

it will if yuo find a safe place to pass the wire throu....

how woudl you implement a magnetic switch?

But on a flashlight body that has 2 switches it would be EASY!

 

[Illuminated]

It comes to mind that this mod might possibly (likely?) disable any low voltage warning/cutoff functionality of the driver.

John

 

[schizeckinosy]

Yes it would, but no matter - the LED will drop out around 3v or so and the 7135 will drop out in the 2.xx v somewhere - I forget exactly where. Since this is not a boost circuit, it will not suck out a li-ion very low.

 

[DIWdiver]

Yes, it will probably suck a LiIon very low, but it would take a very long time. The AMC7135 will meet specs down to 2.7V. It will continue to operate well below that, it just won't meet specs. There's no information about what it will do at lower voltages, but it isn't likely it will stop drawing current before the battery is over-discharged. Same with the LED.

Neither LED nor driver will 'drop out' suddenly, but rather the light will get dimmer and dimmer over time. You'll know the battery is drained long before you do any damage to it.

So in the short term, schizeckinosy is correct that it can't over-discharge the battery quickly, meaning you don't need to worry about it while you are using it, but if it accidentally got switched on as you stashed it in the closet, or if you continued to use the light for hours after it dims to moonlight levels, you might find that when you pull it out to use it a month later that the battery has been damaged or destroyed by over-discharge.

 

[schizeckinosy]

Thank you for the more complete answer. Mine was rather simplistic. I'm curious now and have some laptop pulls here so I might just perform this mod and check the drain!

 

[kosPap]

just to add a note....if one has a 8x7135 chip driver he has no need of drillign etc since he has exposed chips on the outside.
he might as well do it will a piece of wire

And he can isntall a microswitch somewhere in the vicinity of the stars

regarding the drain....
Wouldn't the chips stop functioning when Vbatt falls below LEDvf + Chip overhead voltage?