AMC7135 Issue

[Zeebit]

Got 470mA. I'll just throw this piece of crap away and get a buck driver instead.

Thanks for you help!

 

[ryansoh3]

Could the Vf of the LED be too high?

You could try direct driving the LED (if you dare) and checking the current.

That might even be hitting less than 700mA.

 

[BShanahan14rulz]

zeebit, cap is supposed to go on the output side for long output wires.

Output Capacitor CO and PCB layout:
The output capacitor CO may be removed under certain condition. Please refer to the following figure. If LED and
AMC7135 is located in the same PCB, and the length of the routing path L1<10cm & L2<3cm, the output capacitor CO
can be neglected.

This capacitor goes from the Out pin to gnd

Reverse polarity diode, some say, can have effect. You might could short the diode and see if that changes anything.

Also, your cell isn't at 3.92 right after charging, is it? That would be an indicator of a bad cell, and although sag is noticeable, that cell should still be able to provide .7A without sagging that much.

 

[djQUAN]

Could the Vf of the LED be too high?

You could try direct driving the LED (if you dare) and checking the current.

That might even be hitting less than 700mA.

Zeebit posted the LED Vf on post#6 which I think is a little high but still typical of a white LED

zeebit, cap is supposed to go on the output side for long output wires.


This capacitor goes from the Out pin to gnd

Reverse polarity diode, some say, can have effect. You might could short the diode and see if that changes anything.

Also, your cell isn't at 3.92 right after charging, is it? That would be an indicator of a bad cell, and although sag is noticeable, that cell should still be able to provide .7A without sagging that much.

I suggested bypassing the diode on Post #16 and he still got the same current (post #17) so I guess that's not it.

His battery drops 0.03V with a 233mA load (see post #6) showing about 0.128ohm internal resistance. Not the best but not the worst I've seen.