laser diver circuit whch drive the 250ma and 3 v

[sha173a]

i already have laser driver circuit which is attached..this circuit drive 3v volt and 35ma properly which is the laser drive voltage and current.but i want to drive laser which is drive 3 volt and 250-300ma current so can you help me to modify this circuit.thanks

 

[jiripolivka]

You can use more parallel gates to increase drive current. Or you can design a power operational amplifier for such high drive current. Use a caution, lasers are very sensitive to excess current and voltage spikes.

 

[apolkhanov]

What are you trying to achieve? Do you want to generate pulse signal (like for single pulse rangemeter) or just safely drive laser continuously? Your schematics kind of implies that you want sharp pulses. You need really good laser diode mount with proper heat sink and thermal cut-off circuitry if you want to drive it at 250-300mA continiously. Where does 300mA requirement came from? Which laser diode do you use? If you want to generate pulses of higher power you should look into using power MOSFET instead. Another good alternative for sharp pulse generation is avalanche transistors. Pretty of info in the net.
-Alexei.

 

[sha173a]

this above circuit related to 40ma and 3v,5mw volt laser diode( red laser ). But i have to use green laser which is 250ma,3v and 10mw..so i want to modify this circuit for use green laser...that mean this above circuit drive laser only 40ma so i have to increase the 40ma to 250ma... i want to additional circuit for this current modification. the figure represent the what i going to do for achieve my purpose but i don't know additional circuit is correct or not..thanks

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[HTA]

an current source or switch can be better controlled. You may checkout the iC-HK - it works with 3.5-5V supply and up to 300mA with two channels.

Enjoy your design work!