| 摘要 |
PURPOSE:To ensure the control for the optical output via a simple circuit by producing the reference voltage of the circuit giving the automatic control to the output of the light emitting element such as the laser diode or the like with the capacitor and the diode clamping circuit, thus facilitating an easy control for the base component of the reference voltage. CONSTITUTION:Input signal Sg is supplied to light emitting element LD via the current switch consisting of transistors TR1 and TR2 in order to secure the ON/OFF control according to signal Sg. And the mean value of element LD is detected by light emission output detector PC. The detected mean value is applied to one input terminal of differential amplifier DA which forms diode clamping circuit DC; and signal Sg is supplied to the other input terminal of amplifier DA via capacitor C1. Then the reference voltage added with signal Sg is applied to the DC voltage of circuit DC. And the comparison is given between the reference voltage and the detected mean value through amplifier DA. Then the light emission is given to the voltage at the output terminal in order to secure the equal value to the voltage of the input side, and the control is given to the base of transistor TR3 to secure the constant amplitude of the optical output. |
