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Constant Current Laser Diode Driver Circuit Using OPA2350 OpAmp
- Rajkumar Sharma
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- SKU: EL63344
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The voltage-controlled current source circuit can be used to drive a constant current into a signal or pump laser diode. This simple linear driver provides a cleaner drive current into a laser diode than switching PWM drivers. The basic circuit is that of a Howland current pump with a current booster (Q1) on the output of a R-R CMOS OPA2350 op amp (U1). Laser diode current is sensed by differentially measuring the voltage drop across a shunt resistor (RSHUNT) in series with the laser diode. The output current is controlled by the input voltage (VIN) that comes from Trim pot PR1.
Features
- Supply 3,3V DC
- Load Up to 300mA
- PR1 Trimpot Current Adjust
Schematic
Parts List
Photos
Video
OPA2350 Datasheet
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Hi,
looks interesting. Can you say ZD1 voltage level ?
You can use LM385-1.2 voltage reference from TI.com but the circuit will work without it.
is there any equivalent ic instead of opa2350?
F.e MCP6232T from Microchip
i have to design a laser diode circuit for dental application in pain relief.
please help me in circuit design process
Can you say ZD1 voltage level ?
You can use ZD1 -> 1.05V zener diode.
can I use a LM258 instead
You may try to use the LM258 following the correct connections from schematic.
Hello, May I ask the purpose of C3, R4 (I assume it’s a RC filter, isn’t it?) and R6?
Thank you very much
Capacitor C3 is used for unstable load Compensation to verify that circuit is stable to connect the expansive load like laser diode, R4, R6 current feedback resistors.