foulmist
0
- Joined
- Mar 29, 2011
- Messages
- 1,056
- Points
- 48
@ LaZeRz
actually my friend you are quite wrong:
the IC is PAM2801/PAM2803, which has a 0.095V (95mV) feedback voltage.
I = 0.095/R. With a 0.15 ohm resistor you get 630mA
i have tried with lower resistance - no increase in current....
the IC is designed to work from 0.9V to Vf-0.2V i think it's optimized for 3V input...
anything above the Vf-0.2V will kick it out of regulation and direct drive the diode
the shottky diode is in specs - SS34 i think it can handle up to 2A quite well
the pictures are out-dated the new batches are SS34 and PAM2803 IC...
the old ones were SS24 shottky and PAM2801 IC
you should change the inductor to 4.7uH 2A LOW DCR (DC resistance) to increase the current but you can't get 2A out of it in anyway... the maximum output current is 750mA for the PAM2803 and 350ma for the PAM2801 !!! sometimes you can get a little more out of them...
2A is the switching current - which is NOT the output current!!!
EDIT: the purpose of those drivers are driving a flashlight with LED up to 350mA!!(PAM2801) that's the main purpose of these ICs.. that's why they come with 0.25Ohm resistor...
when trying to drive a laser diode (which have higher forward voltage than the LED's it's designed to power) the efficiency drops significantly and higher currents are very hard to reach (maybe impossible)
here is the datasheet:
actually my friend you are quite wrong:
the IC is PAM2801/PAM2803, which has a 0.095V (95mV) feedback voltage.
I = 0.095/R. With a 0.15 ohm resistor you get 630mA
i have tried with lower resistance - no increase in current....
the IC is designed to work from 0.9V to Vf-0.2V i think it's optimized for 3V input...
anything above the Vf-0.2V will kick it out of regulation and direct drive the diode
the shottky diode is in specs - SS34 i think it can handle up to 2A quite well
the pictures are out-dated the new batches are SS34 and PAM2803 IC...
the old ones were SS24 shottky and PAM2801 IC
you should change the inductor to 4.7uH 2A LOW DCR (DC resistance) to increase the current but you can't get 2A out of it in anyway... the maximum output current is 750mA for the PAM2803 and 350ma for the PAM2801 !!! sometimes you can get a little more out of them...
2A is the switching current - which is NOT the output current!!!
EDIT: the purpose of those drivers are driving a flashlight with LED up to 350mA!!(PAM2801) that's the main purpose of these ICs.. that's why they come with 0.25Ohm resistor...
when trying to drive a laser diode (which have higher forward voltage than the LED's it's designed to power) the efficiency drops significantly and higher currents are very hard to reach (maybe impossible)
here is the datasheet:
Last edited:
