High power Pulsed laser driver circuit

[gegege]

I want to build a pulsed laser driver with this specification:

1. 100A pulse.
2. 10-15 ns FHWM.
3. 100Khz repetition rate.

Any suggestion for a schematics?

Thanks.
Giora

 

[keith1200rs]

Search the forum or look at the bottom of the page where it says "Similar threads".

Keith

 

[gegege]

thanks.
Saw them.
Nothing is answering my demand.

 

[keith1200rs]

So, the application notes in this post are of no use:

https://www.edaboard.com/threads/296865/#post1269783

or this application note on using avalanche transistors to drive laser diodes:

https://www.edaboard.com/threads/296865/#post1269816

Keith

 

[gegege]

Keith,
Thanks.
The app. note from Osram is quite good. i made some simulation and did not get my requirements.
Need PS of 250V to be near my demands.
I want to do it with a 50-100V PS.

Giora

 

[keith1200rs]

I doubt you will get a 100A 10-15ns pulse with 50V to 100V. Check the effect of the 5nH of package inductance on the rate of rise of current for a given voltage.

Keith

 

[gegege]

Kieth,

You are right - the L[di/dt] with 6nf 100A and 12ns rise will give 50V by itself.
So now I have carefully design the traces on the PCB board with a very low Resistance -no more then 0.5 ohm - to give me
the rest of 50V so i can use 100V PS.

Giora

 

[keith1200rs]

I still think you will struggle. I assume you will be using a MOSFET so you have the gate-drain capacitance to worry about as well as drain-source, not forgetting ON resistance, MOSFET package inductance and storage capacitor inductance. One of the fastest solutions for a low voltage would be the Osram SPL LL90_3 as they build the laser/MOSFET and capacitor in a single package but I think that only does 40A. They use a source follower configuration which is quicker but you are limited as to how far you can take that idea by gate-source voltage limitations.

I would suggest making a power supply that will go up to 300V. It is no more difficult than making one at 100V - almost any boost converter IC that has an external transistor can do it. Then, if you have problems at lower voltages you can increase it.

Also, if you have access to simulation, try out your ideas with that first. If not, download LTspice.

Keith