| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical semiconductor element drive circuit capable of decreasing a power supply voltage, and performing a start with safety.SOLUTION: A feedback capacity CFB is connected between the inverted input terminal and output terminal of a differential operation amplifier U1. One end of a first resistance R1 is connected to a power supply VDD. The gate of an N type field effect transistor MN1 is connected to the output terminal of the differential operation amplifier U1, and the drain is connected to the other end of the first resistance R1, and the source is connected to a common terminal. The gate of a P type field effect transistor MP1 is connected to the drain of the N type field effect transistor MN1, and the source is connected to the power supply VDD. The anode of an optical semiconductor element D1 is connected to the drain of the P type field effect transistor MP1, and the cathode is connected to the common terminal. A feedback resistance RFB is connected between the inverted input terminal of the differential operation amplifier U1 and the anode of the optical semiconductor element D1.SELECTED DRAWING: Figure 1 |
