Monolithic loss-of-signal detect circuitry
AssigneeVitesse Semiconductor Corporation
InventorsAdam A. Wu, Balagopal Mayampurath
Life of this patent
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Abstract
A Loss Of Signal (LOS) circuit in an opto-electronic receiver circuit. The LOS circuit includes a current to voltage converter and a comparator circuit. The current to voltage circuit receives a current signal including a DC current signal component from a photodetector circuit included in the opto-electronic receiver. The current to voltage receiver generates a voltage signal in response to the DC current signal. The comparator circuit receives the voltage signal from the current to voltage circuit and generates a LOS signal from the voltage signal by comparing the voltage signal to a reference voltage signal.
Claims18
A loss of signal circuit in an opto-electronic receiver, the opto-electronic receiver having a transimpedance amplifier AC coupled to a photodetector, the loss of signal circuit comprising:
- a current to voltage circuit DC coupled to the photodetector, the current to voltage circuit comprising a current mirror receiving a DC current signal generated by the photodetector and providing an intermediate DC voltage signal;
- and
- a comparator coupled to the current to voltage circuit, the comparator receiving the intermediate DC voltage signal and providing a loss of signal signal.
A loss of signal circuit in an opto-electronic receiver, the opto-electronic receiver having a transimpedance amplifier ac coupled to a photodetector, the loss of signal circuit comprising:
- a current to voltage circuit dc coupled to the photodetector, the current to voltage circuit receiving a dc current signal generated by the photodetector and providing a dc voltage signal, the current to voltage circuit comprising a current mirror receiving the dc current signal and providing an intermediate dc voltage signal, the current mirror including transistors, and at least some of the transistors receive a substrate drive signal provided by a process and temperature sensor, the process and temperature sensor comprising a resistor and a transistor, the resistor coupled to the drain of the transistor and the substrate drive signal being formed at the drain of the transistor;
- and
- a comparator coupled to the current to voltage circuit, the comparator receiving the dc voltage signal and providing a loss of signal signal.
An apparatus for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit being AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the apparatus comprising:
- a current to voltage converter circuit receiving the DC signal from the photodetector circuit, the current to voltage converter circuit generating a voltage signal in response to the DC signal, the current to voltage converter comprising;
- a current mirror circuit receiving the DC signal, the current mirror circuit generating an intermediate current signal in response to the DC signal;
- a load resistor operably coupled to the current mirror circuit, the intermediate current signal flowing through the load resistor generating an intermediate voltage signal;
- and
- a voltage buffer circuit receiving the intermediate voltage signal, the voltage buffer circuit generating the voltage signal;
- and
- a comparator circuit receiving the voltage signal from the current to voltage converter circuit, the comparator circuit generating a LOS signal in response to the voltage signal.
An apparatus for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit being AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the apparatus comprising:
- a current to voltage converter circuit receiving the DC signal from the photodetector circuit, the current to voltage converter circuit generating a voltage signal in response to the DC signal;
- a comparator circuit receiving the voltage signal from the current to voltage converter circuit, the comparator circuit generating a LOS signal in response to the voltage signal;
- and
- a translator circuit receiving the LOS signal from the comparator circuit, the translator circuit generating an adjusted LOS signal from the LOS signal.
An apparatus for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit being AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the apparatus comprising:
- a current to voltage converter circuit receiving the DC signal from the photodetector circuit, the current to voltage converter circuit generating a voltage signal in response to the DC signal;
- and
- a comparator circuit receiving the voltage signal from the current to voltage converter circuit, the comparator circuit generating a LOS signal in response to the voltage signal, the comparator circuit including:
- a reference voltage generator circuit, the reference voltage generator circuit generating a reference voltage signal;
- and
- a comparison stage receiving the reference voltage signal and the voltage signal, the comparison stage generating the LOS signal by comparing the voltage signal to the reference voltage signal.
A method for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the method comprising:
- providing a current to voltage converter circuit operably coupled to the photodetector circuit, the current to voltage converter circuit comprising a current mirror circuit operably coupled to a load resistor and a voltage buffer circuit;
- providing a comparator circuit operably coupled to the voltage buffer circuit of the current to voltage converter circuit;
- receiving by the current mirror circuit of the current to voltage converter circuit from the photodetector circuit the DC signal;
- generating by the current mirror circuit an intermediate current signal in response to the DC signal;
- generating an intermediate voltage signal by flowing the intermediate current signal through the load resistor;
- receiving by the voltage buffer circuit the intermediate voltage signal;
- generating by the voltage buffer circuit a voltage signal;
- receiving by the comparator circuit from the voltage buffer circuit the voltage signal;
- and
- generating by the comparator circuit from the voltage signal a LOS signal.
A method for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the method comprising:
- providing a current to voltage converter circuit operably coupled to the photodetector circuit;
- providing a comparator circuit operably coupled to the current to voltage converter circuit;
- providing a translator circuit operably coupled to the comparator circuit;
- receiving by the current to voltage converter circuit from the photodetector circuit the DC signal;
- generating by the current to voltage converter circuit a voltage signal in response to the DC signal;
- receiving by the comparator circuit from the current to voltage converter circuit the voltage signal;
- generating by the comparator circuit from the voltage signal a LOS signal;
- and
- receiving by the translator circuit the LOS signal from the comparator circuit, the translator circuit generating an adjusted LOS signal from the LOS signal.
A method for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the method comprising:
- providing a current to voltage converter circuit operably coupled to the photodetector circuit;
- providing a comparator circuit operably coupled to the current to voltage converter circuit, the comparator circuit including, a reference voltage generator circuit and a comparison stage operably coupled to the reference voltage generator circuit;
- receiving by the current to voltage converter circuit from the photodetector circuit the DC signal;
- generating by the current to voltage converter circuit a voltage signal in response to the DC signal;
- generating by the reference voltage generator circuit a reference voltage signal;
- receiving by the comparison stage the reference voltage signal;
- receiving by the comparison stage from the current to voltage converter circuit the voltage signal;
- and
- generating by the comparison stage the LOS signal by comparing the voltage signal to the reference voltage signal.
An apparatus for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the apparatus comprising
- current to voltage converter means operably coupled to the photodetector circuit for generating a voltage signal in response to the DC signal, comprising:
- current mirror means for generating an intermediate current signal in response to the DC signal;
- resistor means operably coupled to the current mirror means for generating an intermediate voltage signal in response to the intermediate current signal;
- and
- voltage buffer means operably coupled to the resistor means for generating a voltage signal from the intermediate voltage signal;
- and
- comparator means operably coupled to the current to voltage converter means for generating a LOS signal in response to the voltage signal.
An apparatus for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the apparatus comprising:
- current to voltage converter means operably coupled to the photodetector circuit for generating a voltage signal in response to the DC signal, the current to voltage converter means further including a process and temperature sensor means operably coupled to a current mirror means for generating a temperature and process compensation signal received by the current mirror means;
- and
- comparator means operably coupled to the current to voltage converter means for generating a LOS signal in response to the voltage signal.
An apparatus for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the apparatus comprising:
- current to voltage converter means operably coupled to the photodetector circuit for generating a voltage signal in response to the DC signal;
- comparator means operably coupled to the current to voltage converter means for generating a LOS signal in response to the voltage signal;
- and
- translator means operably coupled to the comparator means for generating an adjusted LOS signal from the LOS signal.
An apparatus for generating a Loss Of Signal (LOS) signal for a photodetector circuit included in an opto-electronic receiver, the photodetector circuit AC coupled to an amplifier stage included in the opto-electronic receiver, the photodetector circuit generating a DC signal responsive to an optical signal, the apparatus comprising:
- current to voltage converter means operably coupled to the photodetector circuit for generating a voltage signal in response to the DC signal;
- and
- comparator means operably coupled to the current to voltage converter means for generating a LOS signal in response to the voltage signal, the comparator means including:
- reference voltage generator means for generating a reference voltage signal;
- and
- comparison means operably coupled to the reference voltage generator means for comparing the voltage signal to the reference voltage signal.
Dependencies are inferred from the claim text.