Ideas for driving LED at 60 MHz

[iamalearner]

Hi

I need to design an LED driver circuit at a frequency of 60 MHz. The LED output light modulated at 60 MHz will be used to excite a sensor and then the light reflected from the sensor will be converted into current for further processing.

Any ideas for driving LED at 60 MHz? I would like to keep the current consumption low too.

Thanks

 

[betwixt]

Re: Drive LED at 60 MHz

Sounds like the World's least efficient design for carrying power.

If you really want to to do this, look at using a laser diode driver. You will find the capacitance across the junction of an LED is relatively high and hence it will have a low impedance at 60MHz. You will need lots of current to drive it.

Brian.

 

[IanP]

Re: Drive LED at 60 MHz

You can consider the same technique as in fiber optic transmitters, that is connecting selected gates in parallel ..
These drivers will typically produce rise/fall times of <3 ns, and a total jitter
including pulse-width distortion of less than 1 ns ..

Rgds,
IanP

 

[iamalearner]

Re: Drive LED at 60 MHz

You can consider the same technique as in fiber optic transmitters, that is connecting selected gates in parallel ..
These drivers will typically produce rise/fall times of <3 ns, and a total jitter
including pulse-width distortion of less than 1 ns ..

Rgds,
IanP

Thanks! I saw that circuit in an appnote from Agilent. We are currently using a slight variation of this circuit. However its consuming around 60-70 mA. I will try to optimize it for current consumption. I was wondering if there is any other way than this.

Added after 1 hours 4 minutes:

Sounds like the World's least efficient design for carrying power.

If you really want to to do this, look at using a laser diode driver. You will find the capacitance across the junction of an LED is relatively high and hence it will have a low impedance at 60MHz. You will need lots of current to drive it.

Brian.

Thanks! I may not be able to use laser diodes as the design is currently designed around LEDs .. but I still may be able to use laser diode driver chips for driving LEDs.
- jeet

 

[iamalearner]

Re: Drive LED at 60 MHz

Sounds like the World's least efficient design for carrying power.

If you really want to to do this, look at using a laser diode driver. You will find the capacitance across the junction of an LED is relatively high and hence it will have a low impedance at 60MHz. You will need lots of current to drive it.

Brian.

The reason we were not able to use laser diodes was that they were not readily available in yellow/amber (594 nm) wavelength range. I am thinking of evaluating ADN2871 (laser driver) for driving LED at 60 MHz. Thanks! - jeet

 

[FvM]

Drive LED at 60 MHz

Do you know optical rise- and falltimes of your LEDs?