Patent ID: 7675951
Filing Date: 2010-03-09
Classification: H01S

Abstract:
1. A semiconductor laser driving apparatus configured to control a semiconductor laser to output a prescribed intensity of laser light, said semiconductor laser driving apparatus comprising: N semiconductor laser driving circuits, with N being an integer no less than 2, each semiconductor laser driving circuit being configured to output a same prescribed amount of current to the semiconductor laser when the semiconductor laser driving circuit is operated, and each semiconductor laser driving circuit including a current mirror circuit connected between a power supply and said semiconductor laser and configured to output the corresponding prescribed amount of current to the semiconductor laser, said current mirror circuit including an input side transistor Pa of a first size and an output side transistor Pa of a second size; a control circuit configured to selectively transmit N control signals to the N semiconductor laser driving circuits, in accordance with a prescribed intensity of laser light to be obtained from the semiconductor laser, wherein each control signal selectively controls the corresponding semiconductor laser driving circuit to operate to provide the prescribed amount of current, wherein a ratio of said first size of the input side transistor Pa to said second size of the output side transistor Pb (first size:second size) in the current mirror circuit is in a range of 1:5 to 1:10, each of the first size of the input side transistor Pa and the second size of the output side transistor Pb being calculated based on channel width per channel length.