LED driver (high current and fast)

[juzug]

Hi!

I am quite a newbie with electronics (and its terms) and maybe therefore I didn't find old threats related this problem even if I'm quite sure that this has been discussed before.

I am building a device where I need bright light in very short pulses (something like 1 millisecond on and 10 seconds off) and I am using LEDs (SSC P4). Now I am looking for driver for leds (one driver for each led). With the driver I want to control (maybe with a potentiometer) the forward current from ~700mA to ~2000mA and willingly more. The control signal to turn the led on is given external via (max.) 5V/0V logical signal and the response should be very fast (not many microseconds). The circuit should also be as small as possible (present circuit is 2cm x 3cm).

I haven't found led drivers that has as high output current. I think that for example MIC2291 (http://www.farnell.com/datasheets/69898.pdf) is quite close but not enough. I think that someone here would know much more from ICs and especially led drivers.

Thank you already in advance.

 

[Meduza]

what voltage is aviable to drive it from?

If the voltage is higher than vF but not overwhelmingly high, use a resistor and a power potentiometer (5w wirewound pot would work) to limit the current and a fast transistor to switch when it gets the signal, that would be a really fast way to do it...

 

[dat2zip]

There are many switched capacitor converters that are specific for the photo flash market. National, Maxim, Linear Technology and others all make versions.

The flash duration can be short. I am not aware of any "variable" controllable models in the style and the most I've seen is 1A in flash mode.

Wayne

 

[juzug]

what voltage is aviable to drive it from?

If the voltage is higher than vF but not overwhelmingly high, use a resistor and a power potentiometer (5w wirewound pot would work) to limit the current and a fast transistor to switch when it gets the signal, that would be a really fast way to do it...

I'm designing this device for 12V battery used normally in cars. I am wondering if the battery is stable enough with only resistor. I mean that the battery won't give always exactly 12V. Also the led itself affects to the current if the circuit were e.g. :
Source - resistor(s) - transistor - led - ground.
Or did I understood you wrong?

 

[juzug]

The flash duration can be short. I am not aware of any "variable" controllable models in the style and the most I've seen is 1A in flash mode.

Yes, there are many different circuits but those are exactly the problems I have noticed. The maybe the variability could be tackled by putting the potentiometer between components output and the led, but the current (limited usually, as you said, to 1A) is a problem together with the short pulses.

 

[jeffsummit]

From a car battery, for a short fast pulse I reccomend:
1 buck converter to generate a regulated 5V. Annode of LED.
2 power FETs w/ series R to sink current, Cathode of LED.