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US 2002/0162953 A1Published application
Optical output control circuit for obtaining stable optical output power
AssigneeNTT Electronics Corporation
InventorsTakeshi Yoshida, Masaki Hirose, Takeshi Inagaki, Katsuhito Toyoda
Life of this patent
Estimating the term…
Abstract
According to the present invention, an optical output automatic control circuit includes an optical output cutoff control circuit outside its feedback loop, and sets an optical output setting voltage at the ground level to prevent overshoot of the optical output while an optical output cutoff signal is being input.
Claims16
An optical output control circuit comprising:
- a light emitting device;
- a drive circuit for outputting a drive signal to said light emitting device so that said light emitting device emits light;
- a drive setting input circuit for outputting to said drive circuit a drive setting signal to keep said light emitting device in a constant state;
- an optical output power setting input circuit for outputting an optical output power setting signal to set optical output power of said light emitting device;
- a monitor circuit for monitoring said optical output power of said light emitting device, and outputting a monitor signal;
- an optical output power control circuit for comparing said optical output power setting signal with said monitor signal, and outputting a comparison signal to said drive circuit to control said drive signal of said drive circuit;
- a first optical output cutoff control circuit for receiving an optical output cutoff signal for cutting off optical output of said light emitting device, and stopping said drive circuit from outputting said drive signal while said optical output cutoff signal is being input;
- and
- a second optical output cutoff control circuit for receiving said optical output cutoff signal, and changing said optical output power setting signal, being input to said optical output power control circuit, to an optical output cutoff level while said optical output cutoff signal is being input;
- wherein said optical output power of said light emitting device is controlled.
7 more elements
An optical output control circuit comprising:
- a light emitting device;
- a drive circuit for outputting a drive signal to said light emitting device so that said light emitting device emits light;
- a drive setting input circuit for outputting to said drive circuit a drive setting signal to keep said light emitting device in a constant state;
- an optical output power setting input circuit for outputting an optical output power setting signal to set optical output power of said light emitting device;
- a monitor circuit for monitoring said optical output power of said light emitting device, and outputting a monitor signal;
- an optical output power control circuit for comparing said optical output power setting signal with said monitor signal, and outputting a comparison signal to said drive circuit to control said drive signal of said drive circuit;
- one optical output cutoff control circuit for receiving an optical output cutoff signal for cutting off optical output of said light emitting device, and changing said drive setting signal, being input to said drive circuit, to a level to reset an operation state of said light emitting device while said optical output cutoff signal is being input;
- and
- another optical output cutoff control circuit for receiving said optical output cutoff signal, and changing said optical output power setting signal, being input to said optical output power control circuit, to an optical output cutoff level while said optical output cutoff signal is being input;
- wherein said optical output power of said light emitting device is controlled.
7 more elements
An optical output control circuit comprising:
- a light emitting device;
- a drive circuit for outputting a drive signal to said light emitting device so that said light emitting device emits light;
- a drive setting input circuit for outputting to said drive circuit a drive setting signal to keep said light emitting device in a constant state;
- an optical output power setting input circuit for outputting an optical output power setting signal to set optical output power of said light emitting device;
- a monitor circuit for monitoring said optical output power of said light emitting device, and outputting a monitor signal;
- an optical output power control circuit for comparing said optical output power setting signal with said monitor signal, and inputting a comparison signal to said drive circuit to control said drive signal of said drive circuit;
- and
- an optical output cutoff control circuit for receiving an optical output cutoff signal for cutting off optical output of said light emitting device, and changing said optical output power setting signal, being input to said optical output power control circuit, to an optical output cutoff level while said optical output cutoff signal is being input;
- wherein said optical output power of said light emitting device is controlled.
6 more elements
Dependencies are inferred from the claim text.