CONSTANT CURRENT LASER DIODE DRIVER CIRCUIT USING OP-AMP

CONSTANT CURRENT LASER DIODE DRIVER

The voltage controlled current 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 then switching PWM drivers. The basic circuit is that of a Howland current pump with current buster transistor on output of a R-R CMOS OPA2350 op-amp. Laser diode current sensed by differentially measuring the voltage drop across a shunt resistor in series with the laser diode. the output current is controlled by the input voltage that may be from an analog voltage source or from a DAC. Scale factor is 1V input equals 1A output. The scale factor VIN/IOUT can be set to other values by choosing appropriate resistor values using the equation. VIN/IOUT=R2/R6 X R-Shunt & R2=R3, R5=R6.

constant-current-laser-diodde-driver-circuit

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Circuit Idea From TI Application

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