A High-Precision Digitally Controlled Current Source Circuit

With the development of laser-based sensing and communication technology, the application of semiconductor lasers in industrial production and scientific and technological research is becoming increasingly widespread. The driving accuracy requirements of lasers are becoming increasingly high. However, the sensitivity of the laser output optical signal to current changes is relatively high, which leads to a high-precision demand for the laser driving current. A digitally controlled current source circuit is proposed in this paper. This circuit consists of a controller, DAC, and voltage-controlled current source circuit, used to drive Finisar's S7500 laser. Parameter model of this circuit, which provides theoretical basis and practical references for digitally controlled current source circuit, is established. The output current accuracy of the circuit reaches 10uA level, and the results of prototype experiment prove the correctness and practicability of the circuit.