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Laser Diode Driver: dampening a voltage spike

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poofjunior

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High everyone,

I'm making a laser-diode driver circuit with an enable that accepts 5[V] logic. It's a constant-current supply (from the LT1083 adjustable voltage regulator) to power the laser, a mosfet acting as a switch to turn on the constant current supply, and a mosfet driver IC.


The mosfet is an N-channel mosfet driven with the LT1910 high-side driver.

Right now, I'm simulating a circuit just like this in LTSpice using an LED with comparable voltage-drop and current ratings.

The problem I'm getting is that I'm seeing a voltage spike at the diode's anode, and it's just enough current and voltage to fry the sensitive laser diode. Does anyone know a way to dampen that spike? I've attached an image of the circuit and waveforms below.

Thanks in advance for taking a look!
 

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    laserDiodeDriver.png
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  • laserDiodeDriverWaveform.png
    laserDiodeDriverWaveform.png
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Try adding a 100uH inductor in series with R1.
 
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