Power output hardware for LV Function Generator

[hgadm]

Dear all,

I would like to design a rectangular pulse generator width adjustable pulse width in LV to build a stroboscope for a power LED.

Are you aware of simple hardware diagrams or devices that could convert the low current output from a PC connected DAQ device to drive a high power LED with a power consumption in the 1-3 Amps range? (Note, the LED is run with constant voltage, brightness is controlled by current).

Many thanks for consideration

Holger

[johnsold]

It sounds like all you need is a switch.  Select a power MOSFET with a current rating of 5-10 A, a voltage rating greater than the power supply voltage to the LED and a gate threshold voltage low enough that it turns on fully with the logic level output from your DAQ digital output.

Lynn

[hgadm]

Thanks Lynn, I am not an electronic expert but are you saying that

• I should connect the signal output to the gate of the MOSFET? Direct with no resistor etc?
• Connect the DAQ signal ground with the ground of the LED driver?
• Would the simple example here work: http://www.electronics-tutorials.ws/transistor/tran_7.html
• Can you give a suitable Power MOSFET type number?

many thanks for your help

Holger

[johnsold]

Yes that circuit would work.  The resistor from the gate to ground assures that the transistor stays non-conducting if the LED power supply is one and the DAQ device is not.

I do not have a part number to recommend off the top of my head and I have some work of my own to do now so I cannot look something up for you.  I may have some time later in the day.

Lynn

[hgadm]

Thanks Lynn, I found a "logic level" FET IRLU 024N with a DS capability >10A - that'll do 🙂

Many thanks indeed for your help.

Holger