Grounding to housing, mcpcb mounted led's and maxflex question

[iggs]

One of the problems with maxfleses I've found is getting all the wires into the 2 'ground' holes

Would I be doing anything wrong to use the aluminium housing as ground and creating an bolt attachement point to collect the various ground wires (power, momentary switch, warning led, main led's etc) and then just have one wire to the maxflex?

As the maxfles will also be heatsunk (heat epoxy via pad) to the housing will there be any problems there?

Lastly what about the cutter supplied mcpcb mounted crees? Will a housing included in the circuit cause any problems with them shorting out or something?

Is there something else I should maybe worry about!!

 

[trout]

Hi Ian .

I dont see a problem the heatsink pad is neg / ground.

and the leds are isolated from the mcpcb base .

Yes I have had the same problem it could do with an extra ground point on the maxflex .

or use thinner wire.

Cheers Chris

 

[iggs]

I do need to look into the size of the wires I'm using, at the moment I'm just using what I've got here!!

 

[dom]

Hi Ian
Don't know about the grounding -but i hook the LED's and power to the GND with the biggest wires i can and splice into the LED wire for the mom switch.

Don't like the idea of grounding the driver.I also think i read that the heatsink pad is neutral as well.

Cheers
Dom

 

[iggs]

Hi Ian
Don't know about the grounding -but i hook the LED's and power to the GND with the biggest wires i can and splice into the LED wire for the mom switch.

Don't like the idea of grounding the driver.I also think i read that the heatsink pad is neutral as well.

Cheers
Dom

Dom,

just checked the maxflex pdf manual

The exposed rectangular gold area just above the (C) TaskLED is a direct thermal interface to the bottom of the switcher IC (on the other side of the PCB). If the power dissipation of the MaxFlex2 board exceeds about 1W it is recommended to affix a heatsink or copper tab to a heatsink to the exposed area. The exposed area is at Ground potential - i.e. electrically connected to the battery GND and LED- pads. This means it is safe to mount the tab to a heatsink that connects to the body of a flashlight, IF the body of the flashlight is the same as the Battery negative or ground.

 

[dom]

Ahh -that's good to know (should have read Trout's post shouln't i -you can hook a switch wire to that then? Or are you going to ground the driver to the body like you reckon?

Cheers
Dom

 

[iggs]

Like you said the wires to the LED's need to be as chunky as possible as do the wires from the battery. I was thinking of using the mounting point for the maxflex heatsinking as an attachement point for all the grounding wires and just run a single, nice thick wire into the other ground solder point on the maxflex. The attatchment point could have the ground from the battery, the switch ground and the warning led ground.

That was the thought any way :-S