Constant Current Laser Diode Driver Circuit Using OPA2350 OpAmp

Rajkumar Sharma      http://www.rajkumarsharma.com  
6405
Project tested

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

PCB

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