| 摘要 |
<P>PROBLEM TO BE SOLVED: To drive a laser diode by driving current with high frequency current of high frequency precision superimposed thereon. <P>SOLUTION: This LD driving circuit 100 is provided with a periodic voltage generation circuit 12, a superimposition circuit 14, a reference voltage circuit 16, a VCO (voltage control oscillator) 18 and an HFM (high frequency modulator) 20. The periodic voltage generation circuit 12 generates a triangle wave Vsaw as a prescribed periodic voltage. The reference voltage circuit 16 generates reference voltage Vref having a positive temperature characteristic. The superimposition circuit 14 superimposes the triangle wave Vsaw on the reference voltage Vref and outputs control voltage Vcnt. The VCO 18 oscillates in a frequency corresponding to the control voltage Vcnt and outputs a high frequency signal Vosc. The HFM 20 amplifies the high frequency signal Vosc, modulates a direct current signal by the amplified high frequency signal and outputs driving voltage Vdrv. Namely, the HFM 20 feeds driving current Idrv corresponding to the driving voltage Vdrv to an LD 102. <P>COPYRIGHT: (C)2007,JPO&INPIT |
