| 摘要 |
<p>PURPOSE:To stabilize the optical output of a semiconductor luminous element by equipping it with a constant current mirror circuit, which consists of a pnp transistor and supplies the semiconductor light emitting element with constant currents, a constant current switch circuit, which controls the on/off of said constant currents, and a stabilizing circuit, which stabilizes the base currents of said pnp transistor. CONSTITUTION:In a constant current mirror circuit which supplies constant currents, resistances 7 and 8 are inserted between the common terminal and the emitter terminal of a pnp transistor 4 for base current compensation and between the base and the emitter of the pnp transistor 4 for base current compensation. Accordingly, the change of the base currents of the constant current mirror circuit accompanying the potential change of the B point which changes according to a control signal can be suppressed, and as a result, the output currents stable even against the switching action can be gotten, and it exhibits the effect that the optical output of the semiconductor light emitting element 6 becomes stable.</p> |
