Patent ID: 6700909
Filing Date: 2004-03-02
Classification: H01S

Abstract:
A driving circuit, operating in combination with a positive operating voltage source, a first grounded current source, a second grounded current source, a grounded modulation current source and a grounded reference current source, the driving circuit comprising:a first adjustment gain assembly pair, including a first resistor and a first PMOSFET connected in parallel with the first resistor, wherein the source of the first PMOSFET is connected to the positive operating voltage source; a second adjustment gain assembly pair including a second resistor and a second PMOSFET connected in parallel with the second resistor, wherein the source of the second PMQSEET is connected to the positive operating voltage source and the gate of the second PMOSFET is connected to the gate of the first PMOSFET to form a connection terminal as a first input terminal of a negative feedback voltage; a first differential gain assembly pair including a first and a second NMOSFETs, wherein the drain of the first NMOSFET is connected to the first adjustment gain assembly pair to form a connection terminal as a first output terminal, and the gate of the first NNOSFET is externally connected to receive a first voltage, the drain of the second NMOSFET is connected to the second adjustment gain assembly pair to form a connection terminal as a second output terminal, the gate of the second NMOSFET is externally connected to receive a second voltage, and the source of the second NMOSFET is connected to the source of the first NMOSFET and the first grounded current source; a first differential output stage including a first differential output assembly pair having third and fourth NMOSEETs, wherein the drain of the third NMOSEET is connected to the positive operating voltage source through a loading resistor, the gate of the third NMOSFET is connected to the first output terminal, the drain of the fourth NMOSFET is connected to the cathode of a laser diode, the gate of the fourth NMOSFET is connected to the second output terminal, the source of the fourth NMOSFET is connected to the source of the third NMOSFET and the grounded modulation current source, the anode of the laser diode is connected to the positive operating voltage source, and the cathode of the laser diode is connected to the current output terminal of the driving circuit; a third adjustment gain assembly pair including a third resistor and a third PMQSFET connected in parallel with the second resistor, wherein the source of the third PMOSFET is connected to the positive operating voltage source; a fourth adjustment gain assembly pair including a fourth resistor and a fourth PMOSFET connected in parallel with the second resistor, wherein the source of the fourth PMOSEET is connected to the positive operating voltage source and the gate of the fourth PMOSFET is connected to the gate of the third PMOSFET to form a connection terminal as a second input terminal of the negative feedback voltage; a second differential gain assembly pair including fifth and sixth NMOSFETs, wherein the drain of the fifth NMOSFET is connected to the third adjustment gain assembly pair to form a connection terminal as a third output terminal, the gate of the first NMOSFET is externally connected to receive a low input voltage, the drain of the sixth NMOSFET is connected to the fourth adjustment gain assembly pair to form a connection terminal as a fourth output terminal, the gate of the sixth NMOSFET is externally connected to receive a high input voltage, and the source of the sixth NMOSFET is connected to the source of the fifth NMOSFET and the first grounded current source; a second differential output stage including a second differential output assembly pair having seventh and eighth NMOSFETs, wherein the drain of the seventh NMOSFET is connected to the positive operating voltage source, the gate of the seventh NMOSFET is connected to the third output terminal, the source of the eighth NMOSETET is connected to the source of the seventh NMOSFET and the second grounded current source, and the gate of the eighth NMOSEET is connected to the second output terminal; and a current comparison circuit including fifth and sixth PMOSFETs, wherein the source of the fifth PMOSFET is connected to the positive operating voltage source, the drain of the fifth PMOSFET is connected to the drain of the eighth NMOSFET to form a connection terminal as an output current terminal of the eighth NMOSFET, the source of the sixth PMOSFET is connected to the positive operating voltage source, the drain of the sixth PMOSFET is connected to the grounded reference current source to form a connection terminal as the output terminal of the negative feedback voltage, and the gate of the sixth PMOSFET is connected to the connection of the gate of the fifth PMOSFET, the drain of the fifth PMOSFET and the drain of the eighth NMOSFET.