Current-sourcing temperature compensated logarithmic transimpedance amplifier using NPN matched transistors with output adjustable voltage
AssigneeCiena Corporation
InventorsAref Pourzadi, Jorge Aguirre, Zhan Xu
Life of this patent
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Abstract
Aspects of the subject disclosure may include, for example, first and second operational amplifiers; and a differential pair of NPN transistors in a feedback path of the TLA configured to convert an input current signal into an output voltage signal, where a first emitter of a first NPN transistor of the pair of NPN transistors is connected to an inverting input of the first operational amplifier, and where a second emitter of a second NPN transistor of the pair of NPN transistors is connected to a non-inverting input of the second operational amplifier. Other embodiments are disclosed.
Claims20
A device operating as a current-sourcing Transimpedance Logarithmic Amplifier (TLA), the device comprising:
- operational amplifiers;
- a differential pair of NPN transistors in a feedback path of the TLA configured to convert an input current signal into an output voltage signal, each of the pair of NPN transistors having emitters connected to one of the operational amplifiers;
- a temperature-sensitive resistor configured to compensate for a temperature dependency of a thermal voltage associated with the TLA;
- an analog-to-digital converter (ADC) configured to receive the output voltage signal from the TLA;
- and
- a current source configured to adjust the output voltage signal to the ADC.
A circuit operating as a current-sourcing Transimpedance Logarithmic Amplifier (TLA), the circuit comprising:
- first and second operational amplifiers;
- a differential pair of NPN transistors in a feedback path of the TLA configured to convert an input current signal into an output voltage signal, wherein a first emitter of a first NPN transistor of the pair of NPN transistors is connected to an inverting input of the first operational amplifier, and wherein a second emitter of a second NPN transistor of the pair of NPN transistors is connected to a non-inverting input of the second operational amplifier;
- and
- first and second temperature-sensitive resistors, wherein the first temperature-sensitive resistor is connected to a non-inverting input of the first operational amplifier, and wherein the second temperature-sensitive resistor is connected to an inverting input of the second operational amplifier.
A method for amplifying an input current signal, comprising:
- utilizing a current-sourcing transimpedance logarithmic amplifier with a differential pair of NPN transistors in a feedback path to convert an input current signal into an output voltage signal;
- compensating, utilizing a temperature-sensitive resistor, for temperature dependency of a thermal voltage;
- and
- adjusting the output voltage signal using a DAC-controlled current source to adjust a dynamic range at an input of an analog-to-digital converter (ADC).
Dependencies are inferred from the claim text.