| 摘要 |
PROBLEM TO BE SOLVED: To obtain high response characteristic of an output current for PWM signal with a chopper circuit in a drive circuit of pulse excitation laser by providing a couple of switching elements to make the switching operation by shifting the phase of each switch and then making small the reactor and capacity of a capacitor. SOLUTION: A chopper circuit of lamp has power transistors TR1, TR2 as the switching elements, flywheel diodes D1, D2, reactor L1 and capacitor C1. The pulse width modulated(PWM) signal output from a controller 1 is input to the base terminals G1, G2 of the power transistors TR1, TR2. In regard to the one period operation of lamp discharge current, when TR1 and TR2 are ON, a discharge current increases via L1, when TR1 is OFF and TR2 is ON, a current continuously flows by consuming charges stored in C1 via D2, when TR1, TR2 are ON again, a discharge current increases because charges of C1 increased, and when TR1 is ON and TR2 is OFF, a current continuously flows by consuming charges from C1 via D2. |
