This is circuit design for a laser diode driver can be implemented using voltage-controlled current source. This simple linear laser diode driver gives cleaner drive current than a switched (PWM) drivers. This circuit is based on OPA350 IC. This is the figure of the circuit.
A Howland current pump with a current booster is used as the basic of this laser diode driver. Q1 is used as the current booster on the output of a R-R CMOS OPA350 op amp (U2). Voltage drop across a shunt resistor (RSHUNT) in series with the laser diode is measured differentially to sense the current. An analog voltage from a potentiometer of from a microprocessor controlled DAC can be fed to VIN to control the laser diode current. Using the component values as shown, the scale factor is 1V input equals 1A output.
[Schematic diagram source: Burr-Brown Products Application Report]
A Howland current pump with a current booster is used as the basic of this laser diode driver. Q1 is used as the current booster on the output of a R-R CMOS OPA350 op amp (U2). Voltage drop across a shunt resistor (RSHUNT) in series with the laser diode is measured differentially to sense the current. An analog voltage from a potentiometer of from a microprocessor controlled DAC can be fed to VIN to control the laser diode current. Using the component values as shown, the scale factor is 1V input equals 1A output.
[Schematic diagram source: Burr-Brown Products Application Report]
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