Constant Current Laser Diode Driver Circuit Using OPA2350 OpAmp

  • Rajkumar Sharma
  • 25.881 Views
  • easy
  • Tested
  • 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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11 Comments
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Mitek

Hi,
looks interesting. Can you say ZD1 voltage level ?

rawan alsaadi

is there any equivalent ic instead of opa2350?

Damian W

F.e MCP6232T from Microchip

naved

i have to design a laser diode circuit for dental application in pain relief.
please help me in circuit design process

Edu Blumer

Can you say ZD1 voltage level ?

Jan

can I use a LM258 instead

Michael

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

Raj

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.

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