Laser driver with selectable output impedance

摘要

The present invention is to provide a laser driver able to select configurations for the high speed application and for the lower speed and the lower power dissipation. The laser driver of the present invention provides a pair of transistors with the differential configuration whose outputs are complementary to each other, and a pair of load circuits connected between respective outputs of the paired transistor and the power supply line. Two outputs of the paired transistor are also connected to the anode and cathode of the laser diode and two load circuits each includes a switch to isolate the output of the transistor from the power supply line to vary the output impedance of the laser driver.