How to use pulse current to drive a LED

[jdmoon]

Hi!
I want to use pulse current to drive a high brightness LED。This LED is about 3v
at 700mA.
It's about a Visible light communication system。The digital signal’s rate is about 50mbps-200mbps。I use a bias tee to get togeher the DC bias current and the digital pulse。My problem is how to supply this bias current。It is about 200mA-700mA and changeable。Can I use a LED dirver？and how to connect it with the bias tee。
In addition，The digital signal need to connect an amplifier before the bias-tee。
How to choose the amplifier？ Can I use a current buffer？how to choose it？
I am a greenhand both in the electronics and English。
I don't know if you can understand me。If you can。 Please give me some advice。Thanks。

 

[biff44]

I would doubt that the led driver can pulse that high. LED drivers are supplies with control loops, and the loop bandwidth is way too small to pulse the led at a 50 nanosecond rate.

There are high speed laser diode driver IC's available, you could drive your LED with one of them and be done with it.

You could also just use a high speed mosfet and a current limiting resistor, although your current control will not be too good.

Also, make sure the LED can switch that quickly. I do not know the response time of a high brightness LED, but it may take time to turn on/off.

You are going to need some big honking bypass capacitors on the power supply lines!